For saving display space on a netbook, you may want to take a look at a tiling window manager, such as wmii. On my notebook, a venerable Thinkpad R50e, wmii proves very helpful.
EDIT:
If you are more interested in minimalistic-looking themes, you could take a look at a Themes pages for Fluxbox. or one for OpenBox. As I recall, themes such as Elfin2 are quite minimalistic and do not require any additional dependencies.