Here, here Gaius...the vanilla BI skins are AWFULL! I keep waiting to see a unit of blue hedgehogs and shinobi ninjas...uurrgghhh.

I'm using this:

http://www.twcenter.net/downloads/db/?mod=759

Doesn't change much in the way of gameplay...(it allows you to recruit the Romano-British units as the WRE) but that's about it.
Does up the Sassanids nicely to and a couple of other units.

I wish Sega looked at some of the mods around prior to BI and took 'em as a challenge...but no...gotta have the sparkly kiddie dayglo units...BANZAAIII