I know I've said a lot on this subject already, but since the topic has been breeched yet again...
I'd say that it is definitely possible to be a successful pilot, or anything else for that matter without a college degree, the obvious exceptions being professions such as doctor, lawyer, accountant, etc. I firmly believe that a person can do anything that they put their mind to. This is not always what I have said in the past; I've revised my thinking a bit.
However, I will say that I am very glad that I completed my undergrad degree--my current job required it, and the job that I'd like to end up doing also makes it a "show stopper" (Not the airlines, yip, in case you are wondering.) I'm also glad that I have the opportunity to further my knowledge and skill through the master's program that I'm in now. I have already seen a lot more opportunities open up that wouldn't have had I skipped college. Education will never hurt you.
There you go. Everybody should decide for themselves whether they should go to college or not. My hope is that they choose wisely.
-Goose