Here are the ATA and SCSI host adapters we recommend:
Promise Technology. An add-on IDE adapter is needed to upgrade systems with older motherboards or in which an embedded ATA adapter has failed. For example, we use an recent Promise ATA adapter to test ATA-133 hard drives in one of our testbed systems that supports only ATA-100 natively. Promise makes a variety of add-on IDE host adapters, one of which should suit your requirements (http://www.promise.com).
Promise Technology FastTrak series. RAID has historically been limited to SCSI servers or high-end workstations, but the Promise FastTrak adapters make RAID affordable by using inexpensive IDE drives. FastTrak adapters are available in for various UDMA levels, with two or four interfaces, and with support for varying RAID levels.
SIIG. Serial ATA hard drives are now readily available, and will eventually replace parallel ATA drives entirely. If you upgrade older PATA systems and would prefer to use SATA drives, you can add SATA support by installing an inexpensive SATA adapter. Although SATA adapters are available from several companies, the only ones we've used are those made by SIIG. They're cheap, easy to find, and just work. What more could anyone ask for?
Adaptec. For SCSI host adapters, we recommend Adaptec exclusively. Adaptec makes many models, from inexpensive models intended to support Zip drives and scanners to mainstream models for high-performance desktop systems, to high-end models for workstations and servers. We've used many of those variants, and have always been satisfied with their performance, reliability, and compatibility. Adaptec SCSI host adapters are universally supported and we never have problems with them. Every time we've been tempted to pay a bit less for another brand, we've later regretted that false economy. If you install SCSI in a system, use an Adaptec host adapter, period (http://www.adaptec.com).
Most people don't think much about cables, but high-quality cables are as important a part of your disk subsystem as the host adapter or the disk itself. We recommend the following cables:
The cables supplied with most high-quality motherboards, host adapters, and disk drives are good enough, if not the best available. We generally use those cables and have never had a problem with them. But cheap cables, such as those supplied with no-name motherboards or sold for $2 in the bargain bin at the computer store, are junk. The best ATA cable we know of is the Belkin F2N1107, but it costs $20, which seems expensive for an ATA cable. Computer stores and online vendors often carry two lines of ATA cables, a "value" series and a "premium" series. Our experience has been that "value" cables are a waste of money whereas the "premium" cables are usually perfectly acceptable.
Adaptec. We have used Adaptec SCSI cables for years and have never had any problem with any of them. Adaptec sells a complete line of high-quality SCSI cables at reasonable prices, and we see no reason to spend more. Belkin (http://www.belkin.com) and Granite Digital (http://www.granitedigital.com) sell top-quality SCSI cables, which are priced accordingly. We've never had occasion to use them, although we know many people who swear by them.
For our current detailed recommendations by brand and model, visit: http://www.hardwareguys.com/picks/hdinterface.html.