Yes, I still use 3.0 when I run a D&D game. It was a great system development, and I really liked the way it allowed gaming in other genres like Omega World and Judge Dredd. I found nothing in 3.0 that I wanted to house rule away. I really liked the minis and plan to use them with the simplified stats when I reprise my 3.0 game. I like Star Wars d20 revised (& minis) for the same reasons.
I play in a 3.5 game currently. I took about 9 months off because it just got to be a grind, but I'm hoping that when this module ends there will be a chance to do something different. At some point, I would consider running a 3.5 game in a specific setting with the D&D minis; but the players would have to convince me that they prefer 3.5 to 3.0. (About the only development I really like is Die Hard.)
I don't like 4.0 much at all. Just not for me. Too many changes. I like the mins, though; but I've kept from buying them since I really don't need the minis or the habit.
These days, I prefer Savage Worlds because it is so much easier to prepare & run. I've found a work-around for 3.0 with the minis cards, but Savage worlds has most of my attention.
It has taken me quite a while to realize that as a GM I need coarse option granularity while the players need fine option granularity. I think the systems and work-arounds I've found will satisfy both needs. The bottom line for me is that an RPG needs to like a perfect storm: accessible rules, cool story and good (preferably prepainted) minis.