be careful of tm regulations
frankly, if you see a good domain (one with lotsa searches - be careful here...search "inside quotes" in Google) and see the .com and/or the .net unregistered, chances are that its either a TM violation, or it isn't such a good domain
all the good domains have been regged, at least in the .com TLD
you might find a couple of .nets and .org, but most good generic TLDs have been taken
you're best bets are with ccTLDs (.us, .co.uk, .eu, .in, .cn, .co.in, .tv, .mobi - stay away from .biz and .name and .ws - they don't sell at all)