Welcome to the AT forums.
Skip SATA drives for now. Get a PATA drive and when you get a machine that has a native SATA controller, you can get a SATA adapter for any of your PATA drives you might want to use in it. It seems that SATA controller cards don't work too well with older systems and the inexpensive ones have poor support. If you pay enough to buy a brand with good support, you could have had a much larger drive or a third one...
.bh.