Ribbon theme is good designed theme with few customization options, like background and twitter. You should try this one, for personal and for business blogs. I would like to see color customization for this gray-red parts and links, and better background customization options. Overall is really really good one. Check it out.
theme is made by http://wakecodesleep.com/
I love this one, is just awesome. And, i know, i know, is premium… but just 9$! That is not much is you want to make something good that will stay there for some preiod of time. If you change themes like you change your clothes, this one is not for you. ;) . This theme have a bunch of customization options. Check it out.
Author of this theme http://tumble.sneak.co.nz/
This one is perfect for photobloging if you ask me, and it have few nice customization options. And not just for photobloging, but all sides tumblr content. You gotta try it. Check it out here.
AOut of this theme is http://new.samstefan.co.uk/
And this dude with sunglasses on this picture is me! Ivalex :)