Great question. I'm a hacker, so I'd be useful from day one. Secondly, I've stuck with one idea for about four years, selling the product for 3 and a half years, so I have no problem adding features or maintaining code.
Here is what matters to me more than a specific idea:
1) I'd like to have lawyers and accountants from the beginning, versus doing it myself.
2) I'd like to start with an investment from the beginning, versus doing it with nothing, therefore being undercapitalized the entire time.
3) On a daily basis, I'd like to work with smart people, versus working with nobody else. It'd be great to have an even ownership split, and to start with each other from day one.
4) I want to afford to live (by live, I mean sustain, nothing special) in a place with other technology folks, so I never feel bored or get an ego, versus living in the middle-of-nowhere.
The reason I'm asking here is because I've considered visiting big universities or even furthering my college career just to meet people for a future project, but it would be logically crazy to do so. The problem is that a lot of CS majors aren't entrepreneurial, and sometimes even immature. News.YC is the best place to find other hackers who want to do a startup. Period. Even better than attending a great computer science school.
I originally followed pg's correct advice to leave school and release "early."
The problem is that after I released "early", I had a small userbase that I gradually grew, and while they helped me find bugs, I got stuck to a small income stream and could never find the time to expand to bigger sources of revenue considering I was fixing bugs, adding features, doing market research, and tech support.
Releasing early is good if you have the means (money, people, contacts, knowledge) to not get distracted, so it's nice that YCombinators and TechStars exist now to take advantage of your highs and give you advice.
However, creating a product while being undercapitalized is futile. From not having health insurance and getting injured for a while, to having to progressively go from a $2/mo host, to a $20/m host, getting tons of visitors to my site from my specific, paying audience--except my site used up the 15GB of bandwidth in half a day. I've also had to make a lot of 'transitional' ideas to keep it all working, all so I could have this experience on a low budget for many years. Another problem was that I was tied to an income stream and keeping up with it for the $500 or $600/mo just to keep the business expenses, keeping me away from doing 2 important things that I planned my first year, because otherwise, I'd have to fold. It's definitely been worth it for everything except money, of course.
For example, I got dozens of great reviews from different paying customers all over the world, and that was the #1 most important thing to me all those years. So I spent this summer making it run on auto-pilot, this time with my own custom software, and a better self-service (another problem is that before, I preferred to have a simple interface and have users e-mail me with questions to avoid being too public, but now, I will add tons of Q&A's so I don't have to answer questions about what the program can do and what I'm planning on adding to it.)
So, I proved to myself that I can make people happy with no investment. Now I want to do it the right way.
In fact, maybe I should do something for people my age while I can still relate--another reason I don't care about the idea is because mine currently targets adults, and having been Student Body President, founding a newspaper club, a chess club, and being in many different unrelated after-school activities when I was in high school, I found I enjoyed it all. But, there is no reason that while you're spending all your time on a project, that you have to do it underfunded, since even for a realistic web service you'd have to be able to support servers costing hundreds of dollars and not annoy users with ads until you can figure out the best way to make it work, and more importantly, start with good resources (teammates, investors, advisors, money).