I have all 3 as well. Here's my opinion on the systems.
Wii: It's basically like a party game system. I play it from time to time, playing Mario Kart Wii, SSBB, Mario Party 8. Zelda was good and Wii Sports wasgood but got boring after a while.
Xbox 360: My favorite from the bunch, most of the games I like are on the 360. Halo 3, Gears, BioShock, Fable 2, etc. Xbox Live is great but a little at times,it could mess up. But, it gets fixed asap so that's why I like paying for the service and I like the overall interface of the 360 as well.
PS3: It's a great system, great Blu-Ray player but I really haven't gotten into it. It has great games like MGS4, Killzone 2, LittleBigPlanet,Resistance 1 and 2, etc. Their service is free which is nice, they have Home which is a cool addition, and their store has a nice looking feel to it. They alsoshow prices instead of points as the 360 does.