nVidia Bump mapping plug-in is a good one, but then again you can have the same plug-in for Photoshop.
For some of you that don't now what that is, it allows you to add dynamic shadows to textures you make for games. Some games that use bump mapping is Half Life 2, CS:S, DOD:S and all their shit load of mods.
Example of some wallpaper texture I made for an HL2 WW2 mod called Resistance & Liberation. You can only notice the bump mapping when the textures are in game, but I thought I show you my stuff.
