Which page navigation is usable?

[Webnauts]

Which page navigation is most usable?

1. Vertical on the left side of the page?
2. Vertical on the right side of the page?
3. Horizontal on the left side of the page?
4. Horizontal on the right side of the page?
5. Elsewhere (then say where)?

Please explain also why?

[WSC-Will]

I'd suggest that site navigation needs to be early on in a page in order to allow people using sequential readers to know where they are and where they can navigate to.

[Faglork]

I suggest vertical, on the right side.

Explanation: You have navigation and scrollbar close together, there is minimum of mouse movement involved when navigating through site/content.

Unfortunately, there is no way to change the side of the scrollbar. If a left-handed person viewed the site, there could be a style switcher to move it all to the other side. I wonder why this feature has been overlooked ...

Apart from that, this is a difficult question, since AFAIK the majority of users expect navigation bars on the left side. So I think there might be a psychological barrier for right-side nav bars. If you build a geek site like alistapart.com, no problem. But for real business? I would stick to left side.

Alex