We have all three next Gens at our house and here is the best way I can come up with to decide.
Go to Gamestop.com, and look through what each system has coming out for it this year.
It has dates and prices for games up through Feb and some in March of 2009. Research the games that look interesting to you and see what ones you want to play more.
Also try to keep tabs on how much you want to spend. If Blue Ray is your thing make sure you take that into account, but honestly prices for one will drop nicely early next year.
All of them have a value that makes them worth the purchase. At the same time though they all have their downsides that make them worthless. It comes down to what a player likes and what her/his friends are playing. Each console maker has finally really begun to embrace what the PC was bringing to gamers years ahead of them and that is the community feel. The ability to simultaneously share the gaming experience with others.
Some shine in certain areas more than others, but eventually they will all have the same features. It comes down to what the buyer wants and it's obvious that the buyer wants multiplayer. The Wii is great if you have kids. The PS3 is great if you like the 1 player aspects of gaming more. The 360 is great for global gaming.
You can argue game titles but the number of titles means nothing to the quality of titles and each system is gaining quality titles and will gain many more in the coming year. Every Fan-boy can say how one is better than another but sit back and take a look. It doesn't matter what system you choose, they are all great in their own way and we are living in a Console Gaming Heaven!
Choose what you want, and if you don't know what you want, wait until you do before you buy.
EDIT: The "Red Ring of Death" that people mention is gone. They fixed that last Version, and people who bring it up need to also bring up "Other" consoles server problems.
