I've got two browsers open, chrome and firefox, and would like to have a shortcut to be able to open a link I have in chrome as a new tab in my firefox window. Right now I do this by clicking 'Copy link address' in Chrome and pasting the URL into firefox, but I would like to have a shortcut defined to do this. Is this doable?
Have you considered just dragging the link? I use both browsers at the same time (each on it's own screen). I find myself mostly using Chrome for gmail etc.. and will get links via email. I just click and drag from Chrome to the Firefox tab bar and the page will open in a new tab. It works in the other direction too (Firefox to Chrome). One needn't limit this to email... basically any link on any page will work via this method.
Might this link be of any handy? http://npopson.com/archives/1022 I believe it's pretty much up for google'ing or somehow changing the chrome's protocols (although there's no in-browser alternative for about:config as in firefox)
Opera has a feature to open the current page in another browser. I don't know what your use case is, but if you need to compare web pages for website development, you could open it in Opera first then right click and open in Chrome, then do the same for Firefox.