SATA and IDE are different drive connection technologies.
in a 7200rpm drive there is little if any difference in the actual drive between the SATA and IDE version. typically the SATA version just uses a standard IDE drive with SATA connections.
with the raptors like you bought they only come as SATA so you need to make sure your motherboard has one.
SATA uses smaller width wires instead of the wide ribbons IDE drives use. this will be better for airflow inside the case, but i've found SATA plugs to be less than stellar when it comes to cables staying connected. if you don't touch your wiring after you are done you should be fine though.
there is really not much difference in speed between SATA and IDE. theoretically IDE is limited to 133 megabytes per second transfer rate no matter how many drives you have on the bus. SATA is limited to 150mb/s (they are supposedly coming out with a higher version soon) and is limited in the same fashion as IDE where all drives share the 150mb/s.
now that you know what the top speed is, you must realize that most 7200rpm drives (IDE and SATA) top out around 50mb/s burst (not constant) transfer. 10krpm drives like raptors burst up to 70-80mb/s. as you can see no single drive can come close to maxing out the allowed speed of either connection type.
the only reason i see for buying SATA drives (typically slightly higher price than IDE of the same capacity) is the smaller cables, or buying raptors. 7200rpm sata is no faster than 7200rpm ide.
ide is still very much alive and well. i had a pair of 36gb raptors in raid 0 and found it was not nearly as fast as i was led to believe. i have since dropped the small fast drives for 2 160gb 7200rpm ide drives and haven't looked back at all. now i have lots of space and the speed difference is quite small.
at this point i would decide the size you want, find the best deal on the manufacturer you want and buy it regardless of sata or ide. if the price is a few dollars higher you might go ahead and get the SATA just to be more current, i guess.
good luck.
