Well, considering the lineup of games is already 10x better than the Wii, it will be worth the price. Probably actually more cost effective than buying a Wii at this point..Rumored to be *at least* $250 at launch.
Right now:
DS lite: 129
DSi: 169
DSi XL: 189
I'm considering buying the 3DS, but $250? I dunno...seems awfully high for a handheld.