I was at a state school paying a reasonable tuition to learn from a quality computer science program. I regret it because although I have written all sorts of frontend code, Ruby, Python, PHP, Java, managed servers, I have still not "finished" learning what a CompSci student learns. I couldn't write my own compiler, I can't tell you which sorting method is fastest for certain data sets, etc. I have learned solely by what is needed at the time, and have created value for businesses I've worked for, but I often just don't have the additional motivation to learn things I don't immediately need. I have SICP sitting on my bookshelf, unfinished.
Anyways, basically finishing CompSci would have forced me to learn some of the theories/necessary base things that I may be missing now.