Hi
I think the best domain extentions are in the following order.
.com - if your website market is global then go for a .com if you can
.net - the next most popular extension and still good if you can't get the .com
.us - As the usa is a huge market to most website that are selling someing or offer a service.
.info - nice for website that offer info on a niche..
.biz - I still like is and some single words go well with this extension.,
.co.uk - good domain extension if you live in the UK and your website market is the UK
.tv - not really hot yet
Thanks
Tom Dahne