In my opinion, which console is 'better' is more about what you're looking for in a console than anything else. The Microsoft Xbox 360, Sony PlayStation 3 and Nintendo Wii all have positive and negative aspects about them that people need to look at and judge before deciding which console to purchase.
The Xbox 360 is a great console when playing games online. The fact that you pay for Xbox Live does make a difference because it grants you an advanced party system, an active marketplace with advanced purchase methods (trust me, Microsoft points instead of real cash can help when it comes to fraud), and increased security when managing online accounts and content compared to the other consoles. Xbox Live also grants you earlier releases for some downloadable content such as map packs in the Call of Duty series. So if you're someone who prefers multiplayer gameplay and wants a secure (well, maybe apart from Call of Duty 4) gaming environment, then the Xbox 360 really is the way to go.
What the PlayStation 3 lacks in online content, it makes up for in entertainment. The addition of a Blu-Ray player mixed with the conventional gaming discs mean that the console is a lot more versatile. In my opinion (and please take it as so) the PlayStation 3 has slightly better visuals when playing most games and movies. I don't know if it's the same for everyone but I certainly do see a positive difference in graphics when playing games on the PlayStation 3 (for reference, I played on the newest 320GB Slim and Lite) compared to the Xbox 360 and the Nintendo Wii. Something has also got to be said for the Playstation Network being free and while the whole hoo-hah with the network being hacked was a problem; they did eventually fix it and most people didn't get off too badly, I guess.
The Nintendo Wii is a console that seems to have got the worse end of the stick. The multiplayer and graphical content seems highly lacking when compared to what the PlayStation 3 and the Xbox 360 offer, however the Wii is one of those consoles that you can't help but having fun on. The innovative motion sensor controller and nunchuck, combined with awesome party titles mean that the Nintendo Wii is the favourable party console and it does have a bit more of a healthy lifestyle focus (moving about, compared to sitting like you would do with the other two consoles) tie in compared with the rest of the line up.
So yeah, I think that all three consoles have something to offer and choosing one depends soley on you and your needs. If you like playing games with a strong multiplayer aspect such as Call of Duty and Halo then the Xbox 360 really is the way to go. Prefer RPGs, or cinematic games? Then the PlayStation 3 will enhance the visual detail (at least, it does for me) of these games and you will find yourself with the most out of your game. Just want to good ol' have fun? Don't care about the graphics or multiplayer? The Nintendo Wii is the way to go for you. Awesome party titles such as Mario Kart and Super Smash Bros Brawl will keep you entertained all night.
To finish off, I will vote for the Xbox 360 simply because I spend my time on it the most and it works the best for me personally. The so called 'console wars' however are odd because I don't think that one console shines out compared to the rest. They're just really good at what they do.