If this doesn't settle down in another week or so post again in case there is something odd going on but at the moment it's all quite normal.
http://www.watchingthenet.com/how-to-reduce-disk-space-used-by-windows-vista-system-restore.html
Asus-SLI Deluxe, AMD x2 4400 (oc'd to 5000), x1900xtx (oc'd), 2GB Corsair XMS RAM 2-3-3-6 (4x512), 500GB Maxtor HDD w/ 32mb cache, 300GB Maxtor HDD w/ 16mb cache, Creative Audigy 4 (Daniel Driver Set), HVR-1100 Dvb-t hybrid TV card, 580W Hiper Type M PSU.
5.0 score on Vista Ultimate x64, 6040 3DMark 06' score on XP