yes also, you have the page file which is just as large as the amount of ram.... i recommend turning that down to about 2gb instead of the 4+ your likely to have, specially on a SSD where space counts.
also, turn off system restore (space saving), and windows search (disk overhead saving), as well as turning off hibernate (who uses that anyways... S3 sleep is so much better)
You can also go to the extreme, and strip down windows with vlite, or RT7lite.... i used vlite a while back for a win 7 pro install on my netbook. fully updated, office 2010, firefox, aim, full java update 23 SKD w/ various editors... using 5.5gb. (i only have 7.5gb to play with on my dell mini 9's ssd)
BUT, for a desktop or big laptop with 30gb of space or more its worth it to have a full win 7 install.... to get down that small you end up breaking some stuff, and its annoying sometimes.