Personally I rate domain hacks, especially perfect ones like last.fm. I think think the dominance of the .com should be challenged, partly because how many .coms are genuine businesses, i.e. do they make any cash, or do they just lose it hand over fist - shouldn't there be a .fail TLD ?
I know there's lot's of issues with hacks like this, but still think they're worth exploring and are a neat way of bypassing the speculative purchasing of .com names.
Try www.domaintyper.com for some neat domain name choices.