My primary is PC, I got a 360 on launch because I loved my original Xbox to death (it still lives!). I bought a PS3 about 7 months ago because I got a great deal on it/ for the exclusives. The 360 and PS3 are really for the exclusives now, my PC takes 98% of my gaming time. I also own a PSP, but I've done very little gaming, I mainly use it as a poor man's kindle and ipod.
Honestly, this is probably the last generation I buy a console, I really regret buying my PS3 (partially due to dying on me during my Christmas break and Sony taking like 6 weeks to get it back to me), the buy in price for exclusives is way too much.