15K.4 36GB U320 SAS, what controller would i need?

This is what PC WORLD "Dream PC" give-away contest has in it and it is using "4" Cheetah® 15K.5 SAS 3Gb/s 300-GB Hard Drives - ST3300655SS.
http://www.pcworld.com/article/id,141628/article.html

The Adaptec RAID 3405 adapter card - $390
http://www.newegg.com/product/product.aspx?item=N82E16816103085

http://www.adaptec.com/en-US/

You could also go the NewEgg site and read the reviews on which Adaptor card most of them are using.
http://www.newegg.com/Store/SubCategory.aspx?SubCategory=410&name=Controllers-RAID-Cards

Also check this one out. HighPoint RocketRAID 2340 PCI -Express X8 SATA I & SATA II Controller Card RAID 0/1/5/10/50 JBOD - Retail
http://www.newegg.com/product/product.aspx?item=N82E16816115031

Hope this helps you out some.

WOW@dreamPC    

this HighPoint RocketRAID looks really good. Would a card with memory on make a big difference to raid 0 performance??

Yes. Also the new Adaptec 5 series that came out this week looks very good, for about same price as the HighPoint card.

http://www.adaptec.com/en-US/products/sas_tech/performance/SAS-5405/

The Adaptec RAID 5405 is equipped with industry-leading dual core RAID on Chip (ROC), the latest x8 PCI-Express connectivity, and 256MB of DDR2 cache to deliver over 250,000 IO per second and 1.2GB/s.

But the HighPoint can support up to 16 HDD's compared to 4 HDD's for the Apaptec 5405.