Right now, Namecheap.com has .us domains for $1.10 (Canadian) and .org.uk for $6.41.
I was tempted to get iAmSoFabulo.us, but I may get something just for test purposes. (I am testing using cloud sites, and it is helpful to have a domain name, vs going with the full domain name that some of the cloud sites provide).
If you are Canadian or want a .ca domain, then netfirms.ca is a better choice (NameCheap.com has .ca domains for $13.03, vs $9.99 at netfirms.ca).
Finally, from what I hear, namecheap.com has deals all the time. It is worth visiting them from time to time to see what is available.