You should really dig up the original sometime. There's a console port of it on some system, don't know if it's the XBox or PS2 or what. But the RPG elements and diversity of choice is magnified at least 10 fold more than the sequel.
I was immediately turned off from the beginning when it loads up and I see that I can't choose what weapons to specialize in, investing in hacking or lock picking, etc. Though I think Invisible War still has the augmentations though, I seem to recall getting far enough that they talk about that.
Glad you enjoy the sequel though, I wanted to play through it, even though I didn't really like it.
I find myself playing quite alot of this again lately. I took a pretty long break from it a year or two ago, just lost interest halfway through Nightmare. Now I'm playing again I guess as a change of pace from the usual high story driven games I tend to play. Also, there's the anticipation of Diablo III, so that has a part to play I suppose.