The SATA is supposedly a little faster. SATA is capable of transfering 150 MB/s, while ATA100 drives are capable of 100 MB/s. The problem is that the hard drives really can't take advantage of this, they just can't read/write this fast. Last time I saw stats they don't use half of that "bandwidth"
So techincally I believe the SATA drive will be mariginally faster until the 8 MB buffer is filled, then they are roughly the same.
Basically it is only marginally better, but the price is only marginally more, so I don't see any reason not to go SATA.
Have you thought about going with a 10,000 RPM drive, they are pretty affordable these days, and performance would be better, from what I have read.
Apparently the ideal use of the faster (meaning ata 133, sata) HDs is if you are hooking 2 up on the same line...I got a SATA drive and right now its giving me hell with drivers...I think I have to have a raid setup (no option), but about your question...If you really are a noob, then go with ATA 100/133, IMO its just simple