This is a comment I posted on WebProWorld after a quick Google search to see what the consensus was on right nav in webdesign. It represents my current analysis of the issue.

I think, when designing your site, you should know which direction visitors' eyes will go. In L-to-R reading countries, this is top-left to bottom-right with few exceptions. In R-to-L reading countries, this is probably different.

There's a new trend in websites (especially blogs) where the content is the message (and, to some extent, the navigation.) In this case, the designer is saying "those links on the right are useful, but you probably want to read this content first."

I think the left-nav assumes that people want to know their navigation options before looking at the content. This is fine for a site like www.wellsfargo.com where there is hardly any useful content-- only links and calls-to-action. They know that 80% of their users simply want to login to their online banking, thus the login box is the first thing you see.

By contrast, www.lloydstsb.com is saying "yeah you probably want to log in, but first check out these other things!" Also note that Lloyds can't make full use of a 1024px-wide screen because many people browse with non-maximized browser windows, thus clipping off the right edge-- Wells Fargo's site can be a full 980px wide because everything important is in the left 80%.

One right-nav site I use as an example is www.southwest.com -- they have a large splash message on the left, and "book a flight" as the leftmost and topmost navigation options. This splash-then-nav strategy would work great for image-oriented sites, like an artist, real estate, or other site that NEEDS a large introductory image or block of content.

Business, government, and conglomerate/departmental websites, however, would probably do best with top-only or top-and-left navigation, since the website's main purpose is to direct you to the appropriate subdivision and not to present interesting content (at least right away.) For example: a right-nav on fedex.com would just be confusing. A right-nav on a large university site would probably not go over well.

I think the emphasis over the past few years of quality content over page quantity is a good thing that ultimately reduces frustration. If you do have quality content that people want to see right away, you can do them a favor by highlighting it on the left, with secondary things like navigation on the right. A design that clearly defines the right-nav will further assist users in "seeing out the corners of their eyes" that the nav is right there, even as they glance at your left-oriented content.