Well, back to the topic at hand...
I finally got my DS today, haven't had a chance yet to try out the Wi-Fi but insofar I'm loving the little thing
The Metroid Prime demo is pretty neat despite it being quite dissimilar to other Metroid games, I was quite lucky in that I got a copy of Metroid: Zero Mission thrown in for free too. I'm quite impressed with the visuals, they're not PSP standard but they do the job and do it very very well. I'll be grabbing Mario and FTM very soon
So, in summation, DS: I love it!