You shouldn't look at it like GB's that you won't fill. You should look at it like an investment in reliability and improved performance.
See, if you fill 60GB of that drive, lots of the time the drive will be seeking 75%+ into the platter. That's a lot of movement. It'll make more noise and have rather high seek times.
But if you grab the 160GB drive, then it's still only seeking 60GB in, which is 37.5% of the platter. The head has to move half as far, so it finds files faster, and you get more speed.
For that very reason, I'd look into the F3 1TB. They come on sale for $49.99 + FS all the time. (every two weeks, approximately) A 1TB F3 would only have to seek 6% in. The head barely has to move at all, so the drive spends most of its time reading/writing rather than seeking. And you avoid those noisy long-distance seeks. There's probably also less wear and tear, although since I don't know everything about HDD internals, I can't say that for certain.
$10 extra gets you roughly 3x the performance and a longer-lasting/expandable drive.
When installing onto it, I'd format it to whatever you need (~60GB), then expand the partition later if necessary.Edited by Kramy - 7/20/11 at 12:04am