2 74GB Raptors in RAID 0 or 1 150GB Raptor by itself?

"Which set up will give me the fastest HD set up?"

The RAID "O" array with a pair of 74gB Raptors will always be faster than any single drive, even with the single drive itself merely a larger Raptor...

(Benchmarks show them roughly equal in transfer rates, with the smaller units sometimes even having an edge...comparing them with the 74GB units in a RAID O, there would be no comparison...)

That being said though...

There are a number of 200-400GB SATA 150 (think Seagate barracuda!)drives beginning to knock on the RAPTORs proverbial door, and you might be able to assemble a still ultra-fast and large RAID O array with one of these for as much money thru careful shopping....