Wii60DS is what I currently own and I'm more than covered with these three.
I can count the amount of PS3 exclusives that interest me on my one hand.
PSP I actually just ordered online, mainly for the homebrew and because I'm becoming rapidly interested in the Monster Hunter series.
My PC is in the low to mid range in terms of graphics and power so it's not much of a gaming PC, but I don't like playing games on PC much anyway unless they're RTS or the occasional FPS.