Which is the best software to monitor HDD temperature? Using WD Black and WD Green here.

And is it better to put OS (which will be the primary harddisk) in my 1TB Black or 500GB Green?

As for the secondary harddisk, I will store mostly .exe files, videos, pictures, musics. Downloaded files will also be saved directly into the secondary harddisk. So which harddisk is better to be used as the secondary harddisk?

Wow, i have been using my old Pentium 4 rig containing MAXTOR 40gb which i bought it on 2003...
Till now, everything is still okay....
And, it is still running goooooood
Throught this period, i think i formatted my hdd for more than 25 times...
MAXTOR