A small hard drive is a like a small house. Less to clean. Yesterday I got a visual alert that my drive was 99% full (Thanks for the hint, Ubuntu!).
I responded immediately in two ways. First, I immediately searched Ebay for hard drives that were are least 60 GB in size. That would upgrade my current one by about 50 Gigs.
Second, I started looking for junk to get rid of.
A short time later I'd found 800 megs of stuff I was happy to be living without, and I canceled the E-bay search.
A bigger drive may allow me to store more, but it also allows me to make a larger mess, lose more in a crash, and anything that involves looking at the whole disk will take longer, like a search, backup, or restore procedure.