I'm thinking about picking up an SSD for my main desktop running kubuntu. But can't seem to decide whether it's best for the system part (e.g. /boot /usr /opt), or the more volatile parts e.g. /home /var etc. What do you guys think? (Please don't tell me to "just get one big enough to put everything on it," I'm only looking for some tax write-off, not to go broke on an SSD. ;-) )