I've got a Wii, I rarely play it now though, and when I do it's only when friends/family are round. I just play games like Mario Kart and Super Mario Bros, group games really.
I've got a PS2 too, which I used to play all the time, yet rarely do now. I'm getting a PS3 soon though hopefully.
Yes. But if you get a decent gaming PC for about a grand, you won't have to upgrade for let's say, three to five years. And PCs are basically an AIO. That's the main advantage. It can do a lot of things consoles can't (multi-tasking for example). And it feels much more easier and realistic when playing FPS games. In games like Just Cause 2 (where you need to perform headshots sometimes), I hear it's quite difficult with a controller.