It's not because it's expensive, I think the US price is great, UK price in some places are selling £200 which is okay (but with no game...). Just that there are so many games I want this year on 360, I'm hoping Last Story or Xenoblade get localised this year on the Wii and of course there is Zelda.
With 3DS I am hyped for many games they have announced, but a lot of the games I am looking forward to will come a long way down the line, some not even confirmed for this year.
I haven't decided yet, but I have a feeling getting a 3DS now, despite having more than enough money to do so, is a big buy for something I might not use so much early on. I know I will get one some time though, it's going to be a great gaming system :P