Most people only type in urls of sites they REALLY like. Most likely people get to your site by clicking on SERPs... so domain names will be less and less important in the future. For marketing purposes, short cool sounding names are best, but for companies just looking for $$ from web traffic... the cool name is less important. If you are doing lots of off line promotion like print ads, opt for the dot com and short and sweet name. If your marketing through serps and pay per click don't worry so much about it.