well macs are pretty much grade A shit because they handle hd real ease and can use the final cut software. i personally like sony vegas ... so im rocking with a Gateway fx series gamers laptop - 2008 model i think - and am loving it.
Get an iMac or Mac Book. They're pricey, but it's sooo worth it. Im getting one soon, but i used them all the time at school for my video classes.