I have all three and here are my observations:
Wii: my kids love it (Smash Brothers and Harvest Moon currently)...for me, meh.
PS3: some great games but dual-release titles usually better on 360. Great controller.
360: best overall for games even though controller not as good as Sony's
I should add that I love the PS3 as a blu-ray player on my 50" 1080p plasma...
Even if the 360 would be best overall for games (which I don't necessarily agree with), I would say though that if you're going to buy just one, the PS3 covers the bases better - a lot of genres, the best PS3 title is just better, especially I think for someone like Matiasz, who isn't going to play for countless of hours on end. There are two main genres though where the PS3 is currently weak - it has less JRPGs right now, ironically, and it has fewer strategy games (though ironically the JRPG Strategy game on PS3, Valkyria Chronicles, has no equivalent on 360). On the 360, Fable 2 is a well received game, and Tales of Vesperia is currently probably the best JRPG and is not available on PS3 (at least not yet). The Command and Conquer games have not yet been released on the PS3 and it remains to be seen if they ever will. It does have Civilisation Revolutions though so it's not totally left out in this genre.
Another notable exception I can come up with is that in Europe, the 360 has a timed exclusive on Rockband 2, which is out on the US on PS3, but over here we'll have to wait for a bit. On the other hand we do have Guitar Hero World Tour already, and the excellence of SingStar makes up for a lot, especially in Europe because there are native language songs from almost every Western-European country, which I think is awesome, but will hardly be appreciated by U.S. gamers
. Also, an aspect of multi-platform releases that is not looked at very much, check particularly the last post in this thread:
http://forum.beyond3d.com/showthread.php?t=50415.
As for multi-platform games often being better on the 360, I do think it's important to realise that when you have a PS3 and only play the PS3 version, that the 360 version is sometimes a few frames faster or has better anti-aliasing isn't going to bother you - it's not like you're continuously playing them side by side.
All in all, I still think MatiasZ is (perhaps even much) better off with the PS3, even more so as he is in Europe in a non-English speaking country. Something like buying Halo 3 and then only being able to play it in Spanish because that happens to be the only language on the DVD, or being stuck with a French interface when you're native Dutch in a country that is as language concious as Belgium is never going to happen with a Sony release. Can you imagine games in Canada only being playable in French? Whereas games like Resistance, Uncharted, Ratchet & Clank and so on you can play in any of 12 European languages and the voice-acting and translations are generally excellent. I personally prefer English and no subtitles, so all I need to do is make that my XMB language. But if I want to have Dutch as my XMB language, I can still switch to English spoken language (or any other) in-game most of the time, and choose English or Dutch subtitles if I want to or if I have visitors, and vice versa. Some friends aren't as good in English and I can play Buzz in Dutch, other times I'll want to play Buzz against English friends. It almost always works great.