3.15 OFW
3.41 CFW (I use it at my GF's home)
3.55 CFW
I use 3.41 for nostalgic reasons, first perfect jailbroken (ok, 3.40 was the first) FW :P
And the latest games don't interest me (I have several new games from before 3.41 still laying around) so there is no real reason to update the 3.41 PS3
Ow, and I have a progskeet laying somewhere in my house. Once I find the energy and time to experiment with it I can go to other FW's also...
Edit: poll needs more options:
* I have more P'S3's with different FW's
* I am able to flash the FW I want