Thats a pretty broad question. I'll try and give a dated answer. Electronics started in lift trucks in the early 70's as EV 185 and EV 210 systems ( feel free to correct if I miss something). As all mfg's progressed, the industry standard became EV 1, then EV100 for most (Raymond has always had their own system). In the late 80's and through the 90's, electronics boomed. Starting in the late 90's, the big names all went to controller based traction and lift systems in their top trucks. It really depends on what your looking for, IC, or electric. For an IC - stay before '02 or so. An electric - it depends on your needs.
In response to steponmebbbboom - I agree the Toyota 5 series was a good IC truck. The early 7 series is as well. Let us know what your looking for and we'll try to help more.