Yes that does seem a little much.
I don't have a 100% accurate reference since i don't have a fresh install of XP; but my system with XP default programs install, Photoshop 7, Macromedia Dreamweaver and Flash, URU: Ages beyond Myst, Call of Duty, Americas Army : SF , Steam (CS, DOD, HL), plus all the extra utilities, small apps, documents, and image capture folder I am only using 8.48GB under a 100GB NTFS partition w/ a 768MB swap file.
I have however disabled system restore, and hibernation which frees up some space ... so those could be eating up some space; as well as like EyoreX mentioned .. your swap.
Oh yes, and I forgot ... an install of MS Office ontop of that.