And yet I still haven't touched Civilization V aside from messing with the video settings. I have the game installed and everything but can never get myself to start a game. I think that may have to do to with burnout from Civ3 from way back when.
Most of the top ones you find are helpful ones like camera controls and such
The IGE can be helpful sometime (though it is the biggest form of cheating ever)
A real world map is also good
I can't even remember all the mods I use
And I still can't get that Hitler Mod to work
Alright, I'm game.
Enter steamid, change "profile" to "card"(or "status"). From there, you can select to use a custom background or the last played game's background. Very useful for tracking the Steam playlog. Alas, I haven't found a similar for thing non-steam games.