I usually don't mess with the CSS layout that much. For one I am no CSS layout expert. Second, there are differences between FF and IE and trying to get them both to play nice can be a pain. You have to know the little fixes for certain situations. Not to say you can't make little changes, just be aware you might run in to problems. Just from my experience...
With that said, there are SO MANY wordpress templates out there, I don't see why can't find one you like. Least find the layout you want, changing colors is pretty easy and your not messing with the layout.
I've seen tons of three column themes, left, right and on both sides. There is something for every one.
You can use the
theme viewer at Wordpress and even sort themes to fit your criteria, though it's not real exact on the sort. The only drawback to the theme viewer is that it seems like they don't have many of the higher quality themes.
And of course there is always Google...
I am kinda liking compact CSS, don't have to scroll down forever to move around.