I have a PS3, because I'm not one of those people who followed the original PlayStation and then the PlayStation 2 only to move onto the Xbox because it's all 'new', and stuff.
There are some things that only the PlayStation 3 can handle. Sure it lost a load of it's intial exclusives, but there's all these companies, including Rockstar, who are making some new games for the PS3 only, because they are confident that when the price drops fairly considerably, it will be the gaming system of choice.
First, graphics. Say what you want on this. Go ahead and say the Wii isn't about graphics. That's obvious. See, the Xbox 360 might, for the time being, boast slightly better graphics, but come on, these are the PS3's first generation of games. The 360 had worse graphics when that first came out. Wait until the 2nd or 3rd generation of games for PlayStation 3, they will be a lot better. Even now, however, the graphics are better on a lot of games. Take Oblivion for example. The graphics are a considerable amount better on PS3, even if you do install the patch on the Xbox 360. Games like Need for Speed Carbon, it's launch games, aren't going to have better graphics, are they?
Next, the games. The amount of exclusives is rising again for the PlayStation 3, and like I said, this is the 1st generation of games for it. It's going to be a long time before it has as much games as the Xbox 360 does, but think about how long there was in between each being released. Now the Wii, that doesn't even get the same games, it has special games made for it. For example, instead of making Resident Evil 5 for it, they make a whole different game, one that the Wii can cope with.
Third, features. The PlayStation 3 already has everything you need for brilliant gaming, and it still has more to come for it in the next few months alone, among them Home, a possible Xbox Live contender. And you might say the Wii has all this stuff like news and being able to check the weather and what not, but it's not hard for me to open up the PS3 web browser and go on to Yahoo! News now, is it?
Lastly, stability. The PS3 just doesn't do that thing the Xbox 360 does where it just dies right after the warranty runs out. Sony didn't rush to get their system out before the others, like Microsoft did, and that's why it doesn't break. It's big and heavy, yeah, but once it's set up and by the television, you're not going to worry about how 'heavy it is', are you?
I'm not a fanboy, I don't dislike the Wii and the Xbox 360 (trust me, if I did, I'd have said so), although I agree with all those who believe that the PS3 will be the market leader within the next five years.