(not exactly needed now anymore I guess, but good for new/other hds...)
Personally I use smartmontools
on all my computers (both servers and desktops). It comes both with 'smartctl' (command line utility to give status reports, execute commands, etc) and 'smartd' (a monitoring daemon).
I have smartd configured to mail me if there's any problem (basicly I configure it like '/dev/hda -a -m my@email -T permissive' @ smartd.conf). Since some time they also have a windows version, which seems to work fine too :).
I usually don't run self-tests though, although it is capable of that, perhaps I'll switch that on if I'm bored [manual shows: '-s REGE Do self-test when type/date matches regular expression (see man page)', so that looks nice :p]. So far I only ran it manually a few times via smartctl.
I've looked in the past at several commercial tools, and although they look nicer, they were all $$$, and this one is free :).