U.S. higher-education system

Does this article apply to you?

If you are at least somewhat smart and ambitious and if you are pursuing a career in which a Master's degree is at all useful (most fields) and you intend to get one, and if the cost of  tuition is an issue, then this article applies to you. The main reason that this article may not apply (other than being filthy rich): a Bachelor's degree is your terminal degree, and you don't have the capacity or motivation to excel above other students at a state-run 4-year institution. If your SATs are above 1200, then your only excuse is laziness. In most careers, a Master's degree is required. Only your terminal school matters; I discuss here how to exploit this.
The Optimal Path

First off, because it's relevant here, my credentials: I'm a PhD student at Stanford. I've seen many people, some very close to me, go through the University system. I've seen what works and what doesn't.
Here's the typical failure story: Pay $40k/year to go to a "prestigious" private school (say, "Brown", a very good school), graduate $100k in debt, and do a Masters at a nameless school that offers a financial aid package, e.g., San Jose State, because more debt would be unbearable. Here's the thing: the Brown education just became worthless.

Employers care almost exclusively about your last degree: you are now a San Jose State graduate.
Here's what I view to be the optimal path: Go to a cheap (but flagship) state school (e.g., Penn State), enroll in the Honors program (due to great high school grades), pay virtually nothing, and then (marginally) get into an incredible Master's program at a school like Princeton; although admissions are unexpectedly lax, most people won't be able to pay that price, but because you skimped on undergrad, you're able to pay it. Congrats: you're a Princeton grad. For $60K. You gamed the system: you got the pedigree for just one years' tuition, at a school you probably couldn't have been admission to for undergrad.
How to game the system

Books abound on the subject. I will give the salient points here.
High School

Obviously, get near-straight A's. I know it seems hard now, but you have no idea how important this effort is to your future; an hour spent to get an A now is as important to your future as 100 hours during your PhD. Man up and do it; I guarantee you will not be disappointed. Take AP classes, and do a few extracurriculars. Obviously, if you enjoy one particularly, then do it. Otherwise, if you're just doing it for show, you might as well juice it up: do debate club and a sport (like tennis or golf). It will (probably incorrectly, but that's okay) show that you're both well-rounded and smart, with a minimal time investment.
Here's what virtually nobody knows, but is very important: DO RESEARCH (by this, I mean, do academic research with the hope of publishing in a journal). Virtually none of your peers will do this--they just don't get it. But, second-hand reports from a Stanford admissions officer suggest that doing some (necessarily, mundane) research for a college professor is the most important factor in admissions. Mass-email professors (by that, I mean, send at least 20 profs carefully tailored and personalized emails offering your services for free), even at very low-rate universities. Take the best position you get--this will likely be the key that moves you to the top of the stack of college applicants. Do you notice that this is a hard, awkward step? Only the ambitious do it, and because of that anybody who does it will likely be successful. That's why it matters.  
Your main goal (unless money is no object) should be getting either a) free-ride admission to a great private school, or (more likely, and nearly as good) b) admission to the "honors college", or its equivalent, at the state school at which you receive in-state tuition. I know it's not your dream college--but trust me, you won't regret not being saddled with $120K of debt. And, state schools are particularly known for sending their top students to great grad schools.
College

Take this phase of your career very seriously. The professors may hold an "A+" carrot in front of you--don't go for it. Or, at least, go for in the context of what it means for your future. Remember, your only point in college (besides having fun and developing as a person) is to get into your chosen Masters program: the prestige of your Masters program determines your future salary, job, and status.
Here's the key: LISTEN: PAY ATTENTION. THIS IS IMPORTANT: Your grades are only 1/3 of your admissions profile. Commonly, students treat grades more seriously than they should. Here are three almost equally weighted components of your grad school application:

1)    Grades: The courses in your major matter most.

2)    Recommendations: Can your recommenders cite specific examples of your great research abilities?

3)    Standardized Test Scores: Are they exceptional? You have no excuse to not have exceptional test scores.

Let me address these in order:
Grades: Of course these are important; but, did your efforts to get great grades detract from the other 2/3 of your application? In particular, are the grades you received in your major `excellent'? Don't sacrifice these grades to get good general-education grades; if you're going for Chemistry, nobody cares that you got a B- in English Literature. Focus on the Chemistry.
Recommendations: Who will recommend you? There should be two types of good recommenders: 1) those who advised you on some serious research, and 2) those whose classes you absolutely aced. If you're entering college, you need to carefully evaluate who these professors are, and enthusiastically engage them. Don't make them write rec's without concrete details; admissions officials are tuned to that.
Standardized Test Scores: These are 1/3 of your application. Do them well. I can only speak of the GRE, because it's the only grad-level standardized test that I've taken. Regarding the GRE, here are two tips:

*    Never get a math problem wrong. Never. If you got it wrong (during a practice test), then re-do the entire test until you get everything right. Never rush yourself.  Once you get in the habit of not making mistakes, it will persist during the test.

*    Start practicing the vocab very early. Two years until you take the test? Perfect. Learn, specifically, the `Barrons' book. If you learn each word, you will get a  near-800 on Verbal GRE, Guauranteed, and you will be instantly considered among the top applicants.
Of the math and verbal tests, only one can be gamed easily. It's the verbal. The math requires some knowledge (some tricks can help with time management, but in the end it comes down to real ability), but the verbal is totally and absolutely game-able. I studied the Barron's book, and there was not a single word on the test that I did not see in that guide; it's a simple vocabulary test, and you have no excuse not to ace it. If you memorize every word in the book (it takes a year to condition your mind to remember the definitions, but only minutes to memorize words thereafter)  then you will get an 800, virtually guaranteed.
Consider also that your composite (math + verbal) score is considered, but that it is easier to get a high score on verbal than math. I got an 800 on math and 740 on verbal; yet my percentile on math was ~92nd percentile, while my verbal was ~99th percentile. Gaming this system is a bit complicated: suffice to say, if you memorize the vocab (esp. over the course of a year or more), your composite score will be excellent.
Rationale

Why should you focus on buying a quality grad school degree, instead of a quality undergrad degree? Here are three reasons

1. Grad schools is shorter. Since tuition in grad and undergrad is similar, grad school ends up costing less.
   
   
2. State schools are respected. Grad schools want great grad students: they're the schools' lifeblood; and, grad schools know that  many, many great students need to go to state schools for financial reasons. It's free-market economics. Exploit it.
   
   
3. Grad school is more important. Particularly, whether you're moving up or down: consider (a) undergrad at Penn State, grad at Harvard, vs. (b) undergrad at Harvard, grad at Penn State. Option (a) is universally considered better, and costs much less.
   
   
4. Grad admissions are more lax: It's far easier to get into a great grad school than undergrad school, if you can pay the tuition (which is the whole point of going to the state school).