OK so now I'm the proud(ish) owner of a brand spanking new Wii (+4 games and a second controller thingy).
I'm impressed by some things and unimpressed by others.
i.e, the controllers are great but not superb, the buttons just seem to be in awkward places for my hands and using two separate controllers to play some games is just weird (i.e in Meet the Robinsons or Zelda).
The really cute interface just seems really childish compared to the no-nonsense PS3 interface.
Graphically the Wii is nothing spectacular, the PS3 is phenominal graphics wise so I wasn't expecting miracles from the underpowered hardware on the Wii but still it is uninspiring. On the PS3 the physics engine (most likely Cell powered) is amazing, water IS water, weather effects are the equal of the most powerful of PC engines and it is easy when playing the PS3 titles to become lost in the game.
The Wii otoh is far less able in this regard and you are always aware of the comic strip style of graphics and unrealistic physics.
For those of you with a powerful PC and Half-Life 2 you will be aware of the realism of the physics engine in that game, the PS3 surpasses that easily (which given the hardware is not surprising) although not on all titles but the Wii is more of a GameCube on steroids than a real contender in this regard.
I don't have an Xbox 360 so I can only go by what I see in the stores, PC World have replaced all their Xbox 360 powered demo rigs for the high end TVs with PS3s because the graphics capablity is higher, i.e full 1080p display output with no delays or jerkiness easily looks better than the 720i of the Xbox 360 on the better TVs (like my 1080p Sharp model). The bigger HD and more RAM of the PS3 here in the UK (they are only selling the high end model) also helps in this regard as more of the games is cached giving smoother gameplay.
Personally the only gripe I have with the PS3 is with the wireless controllers, they are too light and don't feel as responsive as the old PS2 wired ones, in fact we have bought a couple of USB to PS2 adaptors purely to use the older controllers with the PS3 for some games (two player fighter and driving games in particular).
Where the Wii really comes into its own is in mult-player games, they are missing from the PS3 catalogue even though the hardware is there, on the Wii multi-player Bowling or Baseball or Golf is great and although you need to move all the furniture around to avoid accidental injuries is also fun.
I would recommend a PS3 to someone who is likely to want to play immersive single player games (like Oblivion or Fall of Man) and the Wii to someone who is more into family/party play with a large living room (and no breakables in arm-swing range).
Now please excuse me whilst I try to beat my world record time for the Greek Rally on my X1950 Gfx, 4800x2 AMD PC + Logitech G25. Now that's a gaming rig!
Amen-Moses