I've never had a problem with Aspire's, and so far my cheap-o Aspire PSU is serving me just fine. I get ~12.5v on the 12v rail. Seems fine to me, only thing lacking is SATA support.
Will not do You'r chosen Mobo supports DDR 400 and the DDR Kit you chosen is DDR 500
Also, If you got some extra bucks, DFI with the NF4 is much better in case you were going to think of overclocking you'r PC
also if you got some extra cash there, go for a card like x1800xt [dunno why, but every benchmark i seen it working at, it beaten the rest of the cards..]
and here's just an advice about a taste... i'm going to buy a high end pc soon too, the case i picked was the "Thermaltake XaserV Damier 6000A" Which comes with 5 fans [2 exauhst 3 intake] and some more expansion slots for extra fans in future, lot'sa addons and stuff in and out of it... grab a look into it, not sure of its price on new egg but after hours trying to figure out which case would do best in nowdays PC I came to the conclusion it will [since the great cooling solutions it comes with, and some more thigns in it that i liked] but its totaly a matter of taste and needs.