Bookmark previews?

Is there any way to view the URL of a bookmark without opening the page? Or maybe like a plugin to view a preview thumbnail or something?

Right now I have Firefox, Safari, and Opera.

On my PC in opera, when you roll over a bookmark it shows the URL down in the status bar... is there anything like that for macs? I searched though settings and even with the status bar active, it doesn't show a bookmark's URL.

Any help is appreciated!

In Safari, if you have a bookmark saved to your bookmarks bar, a tool-tip with the URL shows if you hover over it.

Is there anyway to do this in Firefox or Opera? I tend to use them more often

The same goes for Firefox. Just put the bookmark in your bookmarks bar.
I never use Opera, its way to buggy and sluggish for my taste.

Can you do this with all bookmarks? Or just in the bookmarks bar?