That's a pretty old hard drive - it was on the market in 2007. It's been out of production for some time now, so I'd be a little worried about reliability, especially if you're looking at a used model.
Hmm... I guess it wouldn't be a good idea to go for the Seagate Cheetah. Do you have any suggestions of some fast hard drives that aren't overly expensive? I don't want to spend much more than $150 on a hard drive/s. I'm buying online.
It depends what you mean by "fast". Modern hard drives with high capacities like 2TB have quite fast transfer rates because data is packed very densely on their platters. But their access times aren't in the same class as a 10K or 15K RPM drive.
It also depends on how much capacity you need. For $150 you should be able to get an SSD with ultrafast speeds that will hold somewhere between 1 and 2 of those 73GB Cheetahs.