Personally I perfer:
Wii (or any game console really, but seeing as the only console that I have that still has games coming out for it is the Wii I chose that.

)
DS
PC
It's not that I dislike playing on the PC, but one reason it's so low on my list compared is because I share the computer with other people. Thus I can't play games on PC just anytime I want to, unlike w/ my Wii and DS.
In addition to that is because if I see a game I'm intrested in for the Wii and DS, I know I can play it. And don't have to worry about the specifications. My current PC is getting long in the tooth, and while it plays City of Heroes, the TTG games and Team Fortress 2 well enough, I can't play the majority of the games that have come out in the last couple years/PC versions of 360 and PS3 games. Especially Left 4 Dead. God I wish I could play that. :/