ebay is definitely not a realistic way to determine value... though it is a good way to determine how desperate some people are to get items that aren't really that rare, just because someone else might get it first.
That said, I've gotten some GREAT buys on there. The prives fluctuate, and sometimes you're lucky and hit the trough rather than the peak. I've also sometimes overpaid, but sometimes getting it now is more important than getting it at a reasonable price. Not often, but sometimes.
ebay only sucks if you lack the discipline to stay below your maximum price and if you lack patience. I'm kind of ambivalent on it. ebay is full of idiots and its artificially inflated prices on some things, but it also sometimes has some great deals and some genuinely rare items. Its a mixed bag, and can be used in smart ways or dumb ways.
