While I must say that I tend to perfer Mozilla Gecko based browsers, but I've always had a soft spot for Opera. It may not be the prettiest browser there is, but it's very small and very fast, and the latest Linux version is very functional. I even think that the new 7.x family with the right skin* is even very pretty.
I may even pay them some money to upgrade my Windows 6.x licence to a Linux 7.x one.
* I hate software skins, they take an already slow GUI and force it to gind at a snail's pace. The only good thing about software that supports skinning, is that there is occasionally a skin that is actually readable.