And here's some stuff in an interesting article that discusses whether links open in the same window or new one.

And more from the design guru himself at #9 on the page.

9. Opening New Browser Windows

Opening up new browser windows is like a vacuum cleaner sales person who starts a visit by emptying an ash tray on the customer's carpet. Don't pollute my screen with any more windows, thanks (particularly since current operating systems have miserable window management).

Designers open new browser windows on the theory that it keeps users on their site. But even disregarding the user-hostile message implied in taking over the user's machine, the strategy is self-defeating since it disables the Back button which is the normal way users return to previous sites. Users often don't notice that a new window has opened, especially if they are using a small monitor where the windows are maximized to fill up the screen. So a user who tries to return to the origin will be confused by a grayed out Back button.

Links that don't behave as expected undermine users' understanding of their own system. A link should be a simple hypertext reference that replaces the current page with new content. Users hate unwarranted pop-up windows. When they want the destination to appear in a new page, they can use their browser's "open in new window" command — assuming, of course, that the link is not a piece of code that interferes with the browser’s standard behavior.