While I liked and used the OGL material for 3e, I played many other games before and during the 3e-era and am currently playing others as well (including Changeling and Spirit of the Century).
Why do I have to pick just one? I'd probably continue with 3.5 for my D&D needs (which is what I'm doing, actually) but we've also got a 4e Shadowrun and a BRP Cthulhu game on deck for our group within the next year or so.