I personally use several different NAS machines here in my home that serve all of my important data such a movies, TV shows, music, etc. using operating systems such as FreeNAS and NAS4Free (because of ZFS implementation) but I do have one machine that I use as a whole-hole HTPC DVR alongside my dual SiliconDust Prime CableCARD tuners which stores all of my recorded shows on a 4x 2TB RAID-5 setup using a 3ware 9650SE-4LPML RAID card with a battery backup unit.
I'm in the market for another either HBA (host bus adapter) with possible hardware RAID-5 support or an actual RAID card that can work with at least 4-8 drives, and I'm looking for one cheap. My 9650SE-4LPML I picked up off of eBay for less than $20 and the replacement battery for the battery backup module cost another $11 shipped. Basically for $30 I was able to add 4 SATA II ports onto my motherboard and gain hardware RAID support for my cheap setup, but that's because it was the cheapest card that I know of that would support the drives I wanted to use.
Among FreeNAS enthusiasts, the most common answer to this question is buying a card like the IBM M1015 and "cross-flashing" it into IT mode which converts the RAID card into just a regular host-bus adapter which allows your operating system to see all 8 drives connected to the card as independent drives instead of a single RAID array, and of course you can keep the default firmware if you want hardware RAID-5 capability. Because of current mechanical hard drives bottleneck though (fastest mechanical drive I've ever seen only reads and writes at around 160ish MB/sec I see no reason I spring for $80+ for a used/like new IBM M1015 since it's a SATA III based card and I'm just as happy with using a cheaper SATA II controller for my needs.
Does anybody have any preferences for cheap(er) SATA/SAS RAID controllers that can be picked up and used in either way for cheaper than the 3ware 9650SE series cards? I know the 9650SE controller comes in flavors that have anywhere from 2 ports all the way up to 24 ports on a single card and at one point I've even used a 9650SE-12ML which supports up to 12 drives in RAID 0, 1, 5, 6, 10, and 50 once setup using either the 3BM (3ware BIOS Manager) or 3DM2 (Windows management console accessed through an internet browser). I'm in the market for a second card since I have a few spare drives I'd like to setup a few RAID arrays/pools with and would like to not break the bank looking for a new card.
Any input/help would be appreciated at this point, because I'm asking around multiple places and would love any feedback into the creation of multiple drive arrays which don't involve motherboard software RAID (since the mobos I use don't have that many SATA ports on them).