I don't think the Raptor is worth it for a few seconds off the boot time and load times. Not unless you're really impatient and have $$$$$$$$$$ to burn.
This config by MarkLuvsCS is pretty nice:
AMD x2 3800+ ($300)
DFI Ultra-SLI ($150)
2GB cheap memory (can use dividers for overclocking) ($150)
7900GT (1 now, buy one in a yr for less then half the price) ($300)
36/74 Raptor for Boot drive ($70/150)
250-320 GB SATA for Storage ($100-120ish)
PSU - Antec/Enermax 550W PSU ($80-100)
I have a few suggestions on this tho:
-Ditch that PSU and get a Fortron 450W instead-$50 bucks and more than enough for your config
-You don't need SLi. When you upgrade and get an other 7900 It will probably be outdated anyways. Besides, one 7900GT is already overkill for most people.
Get a DFI Lanparty Ultra-D mobo instead. It is not a "SLI certified mobo", but it is essentially the same mobo as the SLI-DR, and if you search on anandtech you will find a very simple mod to change it to SLi, as it has two PCIe X16 slots. This mod involves painting 2 things over with conductive paint, and the resulting performance is the same as the SLI-DR, because the 2 mobos are essentially the same
If you want to save a bit more $$, get the EPoX 9nPA+ Ultra. It OCs very well and is an overall great mobo.
-You don't need the Raptor...save the $$$
K that's about it I think...Unless you have a specific budget or specific requirements??