Hmm... I don't think I can pick one. It really depends on what titles have been released and all that.
I got the 360 first this gen (obviously... it came out first). I got a Wii a few months after launch and a PS3 a few months after that. Having gotten my 360 first I started my multiplat collection on that console and it just continued after I got my PS3. Up until 2009 my PS3 didn't get much love but in 2009 it was pretty much all PS3 action for me. Until this summer it stayed that way and then I went back to the 360 for a few months. The last couple of months I've finally started to enjoy my Wii and have a huge backlog on all 3 systems.
If I absolutely had to pick a console (PC is my preferred platform) I'd have to go with 360 due to my friends having that console and being able to play online with them. Had they invested in a PS3 instead I would pick that. Really all 3 machines have been great this gen and you really can't go wrong with any choice.
