Seagate, Hitachi, Western Digital, Samsung, etc. are all good HDDs.
The freeagent drive you selected is a 2.5" drive and compact, if you need that flexibility. If compactness is not an issue, I would go for a 3.5" HDD because of better heat dissipation. Also, look for 32 MB cache instead of 16 MB - 7200 RPM is fine.
Like I mentioned earlier, look for an enclosure with a fan.