I tend not to use texture packs myself but hey, perhaps you do.
Including John P's revamped textures is a nice touch too, making this pretty much the only download needed to modernise Invisible War.
The Visible Upgrade also fixes problems with multicore CPUs and a few display glitches, speeds up level loading, gives options to tweak the HUD a little, and otherwise generally makes Invisible War nicer. Some of the Visible Upgrade's fixes have been possible before, through a combination of player-mode tools and, er, hex editing files, but having it all rolled into one simple update is grand. Oh, and it includes an optional high-res texture pack. It supports modern aspect ratios, including for folks who tape a dozen screens together, has an adjustable field of view, and fixes a few bugs. I found Invisible War technically fiddly and sloppy when I replayed it a few years back, and it sounds like the Visible Upgrade patch by 'snobel' fixes most of my gripes. A new unofficial patch has arrived for Deus Ex: Invisible War, bringing widescreen support and a few fixes to the game that I still think would be remembered quite fondly if it weren't named 'Deus Ex'.