[Rogue Leader]

So I think I'm finally going to replace my aged Alienware. I ALWAYS build my own computers the only reason I got an Alienware is they had a rebate deal at the time that made it cheaper than building my own. I've built hundreds of computers in the past, but haven't built anything recently so I wanted to get a couple opinions:

Firstly the specs (BTW I'm an AMD guy, just a personal preference), I went for high-er end but well tested stuff (ie the mobo is not cutting edge, rather have the reliability), also I don't play games so my graphics card is a little weak but I don't really care. I use my PS3 for games. Looking to keep this under like 700-800 bucks.

AMD Phenom X6 1100
ASUS M4A79XTD EVO mobo
8gb Corsair Vengeance PC12800 RAM
600w PSU
DVD RW drive (for now)
2x 1.5tb drives in RAID 5
1 64gb SSD (with a question)
Windows 7 Pro 64 bit
ATi Radeon 5670ish based video card

So my questions:
1. is a 64GB SSD enough for Windows 7 64 Bit?
2. Am I better off going RAID 10 over RAID 5?
3. Sound... so I have a Sound Blaster Audigy 2ZS that I absolutely LOVE in my Alienware. It is a PCI card with an external "Audigy Drive" that has lots of digital inputs and outputs etc. Creative, or anybody else, doesn't make anything like this anymore, so I was going to just disable the motherboard's onboard audio, pull it from my old computer, and install this instead. However my concern is that this will drag down the performance of the rest of the PC, its a 6 year old card. Any thoughts?

Thanks guys, would post this on a PC forum but I'm not a member of any and I'd rather get the friendlier non "read the faq noob!" responses I would get here.