Ive asked a friend of mine working at Adaptec Munich Germany ,you should take this one ive tolod you the others are as good but will reach end of bus speed earlier on vistas 64er version ...so reason is this is the best and first card made for pcie x1 slot (so less limits)
this is the link to compare u320 cards (driver you get for nearly all off them) but the one at the left is the one ive told you fast and best in price! ...and has reserve of 200% by just one drive 150-300 GB in one drive so you can use 3 drives by 300gb than you come to bus speed end ...but anyway normaly not 3 drives running same time in the average you can do with 10 or more drives agood job ...the driver ive used with 32 bit vista and 64 bit vista as well -100% NO problems! -thats what Adaptecs QC Garanty! the price is not up to date now -old webside ;-) you can get this 29320LPE for 117 EU (*1,54 you got $price)
http://www.adaptec.com/en-US/products/scsi_tech/entry/