Wordoid is probably the best. I've also used http://www.nameboy.com/ (which seems to be down at the moment), and http://domai.nr/ (if you don't mind non-.com, del.icio.us style domains).

Even with those tools, I still hate looking for domain names :)

Good tip. I really like bustaname.com Their second tab is like wordoid, but they have other tools too.