Urgh, down to 1.6GB free space on my 32GB RT. Just deleting the recovery partition now but can't believe I've hit this point already with not that many apps installed.
Don't forget about the sd card slot. But if all your space is taken up by apps, that won't help.
EDIT: Oh wow, nm, I just read the post below mine about installing apps to the card. Didn't know it could do it.