You wont get any better performance on your other one because your master is faster at 7,200rpm so handles data faster. Just leave it on your hitachi hdd.
well yes the hitachi is faster but if you are afraid of your computer crashing and you losing all your data, then i would recommend putting your os on the small drive as you can have 80 gigs of worry free storage.
And what happens if (s)he puts his/her data on the 80GB drive and then the 80GB drive fails? 'sides it's not like one should have and 80GB drive for OS anyways ... partition it into smaller pieces