It's been a while

[smartxtai]

I haven't built a computer in a long time so I am kind of out of date in terms knowing how to build a PC. However, I have kept up with the technology.

I have a few questions that I hope you guys can help me answer.

I am buying parts for my new computer and I am not sure what I need to buy on some parts.

Here are the main parts that I bought so far... my system is going to be a SLI system...

CPU: Athlon64 X2 3800+
Memory: 2GB OCZ Dual Channel Platinum Memory DDR400 PC3200
Graphics Card: (2) eVGA Geforce 7800GT 256MB
Motherboard: eVGA 133-K8-NF41
Hard Drive: Western Digital 74GB Raptor 10,000RPM

I have 4 questions so far...

1. Is a 450W PS sufficient?
2. I know I have to buy some kind of SATA cable for my hard drive, but how fast should the SATA be able to handle?
3. Do I need to install some sort of SATA or RAID controller card?
4. Where do I find the SLI connector that connects my two vid cards together?

If I am missing any other important questions relating to SATA or SLI, then please let me know.

Thanks a lot guys.