the tnt2 is faster than the rage 128, but the rage 128 chip is adequate. of course there is the rage 128 pro chip... that would be around the speed of the tnt2.
if you want DVD, the rage 128 chip is the better choice. you have to use ATI's proprietory program to watch DVDs if you want the hardware IDCT.
TNT2 is faster.
both have their 64bit varieties which are much cheaper, and slower.