Yeah CSS sucks. You have to do all kinds of hacks to get it working right. CSS is heralded because it was better than the old solution, which was styling directly to the HTML, but it's still awful. There's some kind of weird fix you have to do to get things aligned correctly. What I typically do is float all of them to the left and space them with margins. I'll have to go back and dig in those css books to see the 'best' solution.
What makes things even more painful is that some browsers don't support this or that functionality, so you have to worry about that as well. That's one of the reasons people end up using something like bootstrap.
If you feel like taking the easy way out;
http://cssmenumaker.com/
If you feel like taking the easy way out;
http://cssmenumaker.com/