I only use x86 systems these days.
Most of my work is done in Windows (XP), but I try and migrate as much as possible to Linux (Mandrake), which I find much more interesting as an OS.
I also have BeOS and QNX installed, but to be honest they're only there for experimentation, since neither has the software base to satisfy my needs on a daily basis.
Amithlon also has a place on my system, but nowadays I hardly ever use it for anything except Tales of Tamar.
My main system is showing its age a bit, being a 1.4 GHz Athlon with 512 MB RAM and a GeForce2 GTS graphics card.
I still have my expanded A1200 and A4000 systems, but they never get powered up any more. It must be over 3 months since the last time either got switched on at all, and then it was most likely for a few minutes only.
I have no plans to buy a PPC based system in the foreseable future.