I just downloaded this on Steam having bought it months ago and never even installed it.  I played it years ago when it first came out, but never finished because my system wasn't really up to the challenge at the time.  My current system shall crush Deus Ex under its booted heel.  What's the latest on high resolution mods, texture packs, etc?  I've found a few but it's hard to know what the good ones are.

This steam thread should help: link

Not a texture upgrade, but tweaks to help run on the system and look better. 
http://www.kentie.net/article/dxguide/index.htm