If you want both, here's my advice: Go for NSMB Wii first. It's not likely to go down much in price over the course of it's lifetime. Especially if (as Nintendo hope and plan) it becomes one of the ever green Wii titles. I think that's quite likely to happen.
I'd hope that Trilogy sells very well, too, but I just don't see it happening. It'll do decently, but a couple of months after release, the price should go down. Then, you could get an even better bargain (in three amazing games for less than the price of one game) and you may also be able to afford another game in Q1 for your birthday.
Obviously, nothing I've said will definitely happen, but I think it's a likely scenario, and if I were you, that's what I'd do. Plus, as others have mentioned, NSMB Wii will be a great game to play with family and friends over Christmas.
Whichever way you go, you'll make a good purchase.







