if your going to get a cheap card, it's going to be more then likey pesduo raid (the raid support is done in the drive in the system and not on the card). and if you are going to go that route, i would recomend using linux software raid, and not a card, mainly because if the card dies, and you can't get a replacement, your pretty much screwed. if you use linux software raid, it's alot easier to managed, and alot more portalable
if you want pure speed, go raid 0 (striped), if you want some speed and don't much losing a bit of disk space go 1 or (0+1), personaly i always use raid 5 or 6, basicly raid 5 is the size of all the disks -1, and raid 6 is the rame, but -2, and you get most of the speed from all the disks (raid 5 is basicly striped and paridy so you get speed and backup).
raid 0 - lose a disk, ALL data gone (pure speed)
raid 1 - lose a disk, still have data (speed and backup)
raid 5 - lose a disk, still have data (lotsa speed and backup)
raid 6 - lose _2_ disks, and still have data. (a little slower then raid 5 but high level of reduancey)
hopefully that information will help a few people.