At the risk of destroying your productivity for the day, you can probably fix that annoying line over your line numbers (that is, http://imgur.com/GhaNq) by messing with your fringe-mode variable. I think I remember its presence having something to do with a conflict between fringe-mode and linum-format.

Thanks ! I've been searching a long time for a fix for this. I switched linum-format to " %d " and this is clearly better.

Would you mind sharing the exact settings you're using in your .emacs? I'm struggling to find a happy medium in terms of weight, height, etc.

This thread could be social engineering to get someone to show some code in their editor which is 'secret sauce' to the project. :)

Can I ask what color theme you're using there?

Sure. It's the "wombat" theme included by default with Emacs 24.