I think I'll just wait for my full frame body purchase to get some really nice lens. Until then, I'll stick with sigma for the budget crop body lenses.
That's the nice thing about lenses, they hold their value. As long as I take care of my new (used) lens, I should easily be able to sell it for what I paid for it. Heck, I flipped a new lens on ebay last week for $50 more than I paid for it new. If I go ff, I'll just sell this one...