Just remember you can buy a 'new' domain name for a few dollars, and a used one may be damaged goods.
Shop around, think about what you need, and search for a few possibles.
My method has always been to sit around with a few friends and a few beers, brainstorm a list. Then (when the beer's worn off!) rearrange them in order from best to worst, and see what is available. You'd be surprised.
It's also worth checking ebay for names; I bought a good four-character .com for $20, and picked up many ideas (for free!)
