Well, I'm not sure what you are expecting, but the textures have significantly changed and improved. The building textures on Liberty Island, for instance, look MUCH more detailed. They don't have any advanced effects, though - at least not as far as I can see.
But I'd say you can immediately see the difference no matter what.
I didn't install the NVTextures to a separate folder - I just replaced the existing ones. Not sure if that would help you, but otherwise I'm stumped as to what it can be.
Oh, and if you're serious about playing it - I highly recommend the Shifter mod - as it contains some nice gameplay additions. Most importantly, it rewards XP for appropriate actions ala Deus Ex HR. Meaning, you get more XP the more "skilled" you play.
Heh.. it turns out I overlooked something.
I changed the texture folder path line in the deusex.ini file per the directions, but I made the mistake of only changing the file in the installation folder, not the one in my Documents folder.
I saw the difference as soon as I restarted the game again. Big improvement on certain textures.. especially wood and stone, and a lot of objects in the environment. I wish they had touched up the character models as well, but it's a nice upgrade overall.
I googled that Shifter mod. I like what it does with the XP bonus's, but I was disappointed to see that it also adds fan-made weapons, etc to the game. It changes a little too much for my taste.