Man that's a tough choice.  I don't envy you.  I had the choice made for me:  My PC can only hande the minimum specs (I don't want it to run like crap), and I won't have a 360 till the end of the year.  So for now, just MP3 for me.  

I wasn't one of them.

 E3 traditionally focuses on this year's titles, and most new games take more than a year to develop. By the time everyone really understood how much of a phenomenon Wii was becoming, there were only a handful of months to start developing titles. I imagine very few were even far past the planning stage, let alone in good enough shape to show off at E3. The only stuff they could have to present would be ports, quickie games and stuff that had been in development at the time of launch.

I doubt we will really see the fruits of the Wii's success until either late this year or, more likely, E3 2008.

 Like I said, that list was just off the top of my head and there are plenty of games I missed.  Anyone who thinks any of the three systems don't have at the very least a decent line up are simply ignorant.

And yeah, deciding between the Bioshock and MP3 sucks.  Right now I'm leaning more towards Bioshock just because I recently got Mario Strikers so I want to give my 360 some attention.  I'm sure I'll still pick up MP3 at some point, just gotta wait until next paycheck and a dry spell. 

@ Naznatips

You seriously think Soul Calibur Legends, Nights, Boogie, Ghost Squad, Rabbids 2, RE: UC and Medal of Honor were all being made before the success of the Wii was known???

Also remove Dragon Ball Z from there cause it's another PS2 game that is also being released on Wii for a cash in.

Aren't most of the big teams that make major games still working on the same PS3/360 games that were announced long before the Wii hit the scene? Essentially your asking "Why aren't more dev's announcing major games while in the middle of other major game development?

What about all these 3rd party games that keep getting announced now for 360 and PS3? Not all of these games were being worked on before the Wii sold welll...

 And I'll say this again: while I was looking for a job last January-March, I visited and talked to a very large amount of studios and just about every one of them had at least 1 Wii game in the works (some further along than others).  Some of those may never see the light of day or won't be anything spectacular, but a lot of them did look like a lot of fun.  The games are coming.

The reasonable people here are not saying that 360/PS3 development is simply going to stop, that it is going to go from 90 percent 3rd party development to 0 percent in the course of a month. It's a very gradual change. 

Simple example: we can verify that the following games were in development when the Wii and PS3 launched.

Resident Evil 5
GTA IV
Final Fantasy XIII
Devil May Cry IV
Metal Gear Solid IV
Tekken 6

That's nearly every key third party "hardcore" franchise in existance. Not only does this explain why such games aren't coming out on the Wii, but it explains why these key developmental resources -- some of the top devs in the industry -- are still locked in to 360/PS3 projects. 

If we can agree that the developmental split between the Wii and 360/PS3 in terms of funds was somewhere around 15/85 when the systems launched, I expect it to be around 30/70 by year's end, and I expect that ratio to continue to increase, albeit slowly. Which highlights my point; this isn't some dramatic, sudden shift, where everyone drops all their projects and all the money they've sunk in to them in order to make Wii games. 

Even once the Wii has rocketed well past the PS3 and 360 in user base, I don't expect development for the PS3 and 360 to literally stop completely. In fact, I expect both systems to get some fabulous games, especially for traditional fans who love MGS and Tekken style games; that's the arena that the 360/PS3 clearly have established a user base in. Think of the PC -- it's been a sidelined platform for some time now, and its influence continues to shrink. But it still has some awesome games, and particularly several of my favorite games of all time. I expect the 360 and PS3 will do the same for you. 

There's a big difference between saying "PS3 and 360 development will instantly stop, and 100 percent of resources will be diverted to the Wii by year's end," which is absurd, and saying "As the Wii's user base continues to grow, more and more developmental resources will gradually be moved to the Wii," which is both logical and empirically valid.  

October-December is going to be HUGE for Nintendo. With a pile of third-party support, as well as the "killer three" (Metroid Prime 3: Corruption, Super Mario Galaxy, Super Smash Bros. Brawl) coming out, they are going to have a phenomenal rest of the year. I don't know how you get off saying Nintendo has no third-party going.

That said, January-March is going to be massive for the PS3, the line-up is looking fantastic, likely enough to pull a sizeable amount of sales out of the normally-dry post-Christmas sales season.