Techcrunch is hosted on wordpress.com - sure it's the VIP service but there are tons of big sites on WordPress. Either spend some time customizing a theme or look to spend $50-$100 on a premium theme - this will make you look much more professional, and there are many themes out there that don't even look like WordPress. If your idea will work on WordPress (or tumblr) then I think you're crazy not to use it.

http://wordpress.org/extend/themes/

http://wordpress.org/extend/themes/commercial/