personally I´d go with the 360 out of pure logic logic, will you have time to really play all those Wii, DS and VC games...??? I´d say if you buy two of each, that will last you a while...you can catch up on the rest when they are cheaper, having a Wii360 will give you a bigger and better selection of games to play (the big three plus the 360 überlineup this x-mas will give you lots of choises). Another thing is the 360 game library... no not the one you can buy, the one you can borrow from you friends, I bet there are a lot of games they have finished just waiting for you.
Its always better to have more consoles and more game options, lots of great games in the furture will be only Wii or 360/PS3, so haveing one of each will give you all games you want exept the PS3 exclusives, the games you whant now won´t run away (and will get cheaper) but it might take some time till you have enough money to buy a 360 and some games.