See, the thing here is, a lot of you are calling the Wii "childish" based on the "kiddie games" available for it. Yes, there will be kiddie titles on the Wii - hell, they crop up on every console - but that doesn't make it childish. It's like saying Disney only makes kiddie shows and films; you did watch Pirates of the Carribean, right? Now go play Resident Evil 4: Wii Edition for goodness' sake
Now, to the merits of each console. The PS3 has Blu-Ray (but it's not a real advantage yet because of the format war), high-definition graphics better than in most Wii games (but don't expect Sony to deliver on it's pre-release eye-candy promises), and of course the DualShock 3 (even if SIXAXIS is cheap Wii remote knock-off). Also, a lot of upcoming PS3 titles will be exclusive to it, and the console has a much wider range of support from developers; there aren't many developers supporting the Wii at this stage.
The Wii, on the other hand, is filled to the brim with originality - creating Miis and weather and news updates are just a couple of new things Nintendo have had a crack at, and that's not including what Wii developers are coming up with - you don't see many games like Wii Sports or Red Steel for example. In a way the lack of power is a plus, since it's going to force developers to think of new stuff instead of thinking about the best way to show something blowing up into a million pieces. So far it's also outsold the PS3 and Xbox 360 (last time I checked anyway), and I have never heard of a Wii experiencing system failure, bricking or even three red lights that form a semi-ring and mean no more playing on that machine (sorry Micro$oft, couldn't resist); kudos to Nintendo for getting it right first time. The light-gun genre is a lot more accessible with the remote as well; no more buying G-Cons separately (though I bet it's only a matter of time before a full-blown Wii light-gun is released), and Virtual Console is a huge plus (assuming you're willing to part with some extra cash for the Classic Controller and Wii Points). Unfortunately though I have yet to see a Wii game make full use of online capabilities, which kind of feels like we're regressing back to Multitaps (only with wireless remotes and without those black bulky things reserved almost exclusively for Mashed these days, i.e. the Multitaps).
The final verdict: PS3 is definitely the safer bet - with lots of hot new exclusives coming up and even hotter visuals, you're pretty much covered. But if you're looking for something more original that doesn't have reports of widespread crashes or bricking, then the Wii is for you.
OK, I'm done now