I am lucky enough to have an equally obsessed partner, so we have a Wii and an Xbox 360. The Wii is fab, but I found that we abandoned the main games (such as Zelda) and now use it as a party system - playing Super Monkey Ball/Wii Sports multiplayer stuff when we have parties.
I thought I was not going to be able to play GTA IV, which is top of my gaming agenda for 2008, because I can't afford the prohibitive price of a PS3. Happily I now have the 360, and have a pre-ordered copy of GTA IV waiting for me. I would have gone for the PS3 because I think it's a better system, but it's just tooooo expensive. With Xboxs becoming more affordable (they've just announced a European price drop so entry level is �159.99 compared to around �320 for a PS3) I think this will become the system to watch!
Price is definitely an issue - however I do have to say that we are watching a lot of BluRay DVDs and that a PS3 is much cheaper than pretty much any BluRay player on the market. So in that sense it was a great buy. But really out of the 3 systems we have, we play the Xbox 360 the most by far.
Well and the PS2 is in the basement as my "dance machine"
Bought the 360 first due to the expense of the PS3 but got a bonus at work which covered that as I wanted the blu-ray player and although I have seen it called a cheap blu-ray player it has had some very good reviews. The PS3 was and still is in my opinion the better machine by far. Didn't fancy the Wii when I first saw it but have come round to the idea and have just ordered one for the family..
I don't know that any one is really inherently better than the other. To me it's like choosing a favorite pet They all have their advantages and disadvantages. For example I like the 360's online system FAR better than the PS3 - but they've put a lot more time and effort into it.