By the way, you should definitely download the patch for VI. It will patch some serious bugs

Downloading a mod depends on your preference. Most of them affect your installation seriously so I would advise a seperate installation for the mod; just copy and paste your installation folder. It will cost you HD space, but you can still play MP-games with the original.

We have in the Dungeon:
MedMod: provides greater challenge and adds loads of new units. It takes a while to adjust to.

BKB Supermod: provides greater challenge but I believe it is mainly focused on better historical accuracy.

Hellinic TW: with this conversion you can play ancient warfare before RTW hits the shelves. I think you should wait till mid April since then they will release a new version with hopefully a whole lot of flip's new unitgraphics.

Napoleonic TW: this conversion is the most finished and there are often played MP-games with it.

Then there are several smaller mods that are great if you want small changes. They are not lesser, they just don't adjust the game so much. They're also most of the time in a more finished state.

Go to the Engineers Guild for more information.

Cheers, Duke John