After reading this thread I decided to try out the free trial for endnotes and mendeley. Endnotes was harder to evaluate because it was rather not user friendly, and I feel it may not have been quite suited to my needs as a student. It may be that with some practice I'd be more impressed, but not being able to read articles from pdf or websites seems like a big minus. I also couldn't use it to access any of my usual databases because I need to go through the university to get into them, which didn't seem to be an option.
Mendeley I was more impressed with, however it did seem to have a few bugs. While adding new things to my bibliography it would also randomly delete characters from my old entries. I didn't really feel I could trust it to do my references without errors, which would seem to limit it's use quite a bit. Might be worth playing around with more though to see if I can somehow resolve that.
I'd be curious about other people's experiences, because something like this would seem to have the potential to be really useful in the long run.