The Adaptec 1210SA is probably the best on a budget. Chain stores carry them for around $79. This 2-port card can do mirroring or striping. Native SATA (no bridge chips) so the performance is decent even though it has no cache memory. The management software is a decent, if not excellent, browser-based package...you can check your array status locally and remotely.
The card comes with 2 1-meter cables (so you're set even if you have a very large case), a flex-height descender if you have a small case, and drivers for Windows 2000 & XP, Red Hat, and SuSE. The XP drivers work fine in 2003, even though it is not supported.
The only negative feeling I have about this card is...it has no connector for a status LED...I like my blinkenlights...
Product home page:
http://adaptec.com/worldwide/product...erial+ATA+RAID
Generally speaking, there is a huge jump in cost to go from a 2-port SATA card to a 4-port or larger. Expect to pay over $300
for a 4-port card by Adaptec or 3ware, or around $200-250 for a Promise...but those cards have cache memory, hardware XOR engines, hot-plug support, more functionality.