just the term 25 ms doesn't really say how much ghosting (well that's not even technically the correct term but oh well) you'll see. It makes a lot of difference which type of panel they use as well, or at least it does for bigger LCD screens, so I assume the same goes for the small ones. Also the smaller the screen the less you're likely to notice ghosting. Anyway, the reaction time is largely a marketing term that doesn't always directly relate to the amount of ghosting visible.
As you say, there wont be all that many apps that you're likely to notice it on anyway, I'd just wait to see it irl... I'm lucky enough to not really notice all this ghosting business too much, played 3D games for years on a laptop screen that, in hindsigh, has terrible ghosting, and never noticed it durnig play, so I couldn't tell you even if I already had a GP2X.
edit: right... blur... why the hell did the term ghosting keep popping into my head... nightshifts getting to me I guess...