hmmm.....
bargain components that are okay=blaupunkt(70$ish)
mid priced ones, which will do admirably for most people=infinity reference (190$ish)
my dream set= cdt 3 way (400$ish)
go with 6.5s, weather you have a subwoofer or not, you never want a sub crossed over to high, i have mine at 75 hz and i would feel uncomfortable with making 5.25s play down to the 70 hz range, although im sure they CAN.
and of course, theres always the mix and match route. in which case, go to parts express . com and have them send you a catalogue :p