Yeah, well I hate space management with a passion. I upped the HDD in my laptop to 640GB (and 8GB RAM) a while ago, because I didn't want to be caught high and dry without any space. I don't backup everything, just the stuff I need. Some big ISOs/DMGs and my Steam directory are ignored, as well as Boot Camp.
My Desktop only has a 115GB SSD, but I have 1TB Storage drive for media/downloads and a 2TB (2x1TB) RAID0 array for games. I hate have to shuffle stuff around, though. Considering finding the same model SSD as I have and running RAID0 on them for 230GB that reads/writes at over 550MB/s. Not having Sata3 on that board means I won't get the full speed of current SSDs.
You back up regularly? That makes you one of about 1% of people.