just going to say a couple of things on this topic (being a UK-er)
Firstly, you've got to remember that this is quite a big deal because the PSP has only been out here for a month or so, which the DS has been around over six months (and most of the big nintendo peeps bought them on import in december) (while importing PSP, although big, wasn't as wide spread).
Secondly, although GTA:LC will be a big deal for the PSP and undoubtably boost sales, it launches at a point where the XBox 360 is close enough to start displacing PSPs on peoples christmas lists AND around the same time as Mario Kart DS is launched. The online feature of Mario Kart is enough to make pretty much anyone I know who played it's previous incarnations, shell out ÂŁ100 in order to prove to their now distant friends who really was the post-pub Mushroom Cup king.
I honestly think the incredibly delayed launch of the PSP in europe has put it in a position where it could be gazumped by both the DS and the 360 this christmas.
There's no doubting this will change as time goes on, but I think this christmas the iPod Nano, the DS+Nintendogs+Mario Kart and the XBox 360 will be the big three under the tree