Because of the issues with the earlier versions of RTW (1.0, 1.1 and 1.2 in particular, such as the siege save-load bug in which the computer would break off sieges and go back to it's lands every time you ended the turn you loaded into), I insist you upgrade to the 1.3 patch if you don't have BI (installing BI will auto-patch RTW to 1.3), and then to 1.5 (if you do have BI installed, or are installing it, etc, all you need is the 1.6 patch which also auto-patches RTW to 1.5).
I take it you just have RTW, so just get 1.3 and then 1.5. Then, search the downloads here and at twcenter.net for decent mods. I particularly insist on Terrae Expugnandae, a gameplay-orientated mod. It uses the latest version of the Mundus Magnus map, and reskins all the factions, makes rebels extra strong so that when factions finally do go to war with one another, they're more built up, etc. Check out the following link:
http://www.twcenter.net/forums/forumdisplay.php?f=114
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\/\/\/\/\/\/\/\This is Bunny roasting on an open fire. Yummy!