I enjoy both APC and Tool, owning the full catalog for both and having seen both in concert. And while I wouldn't exactly call APC Tool-lite, I can get the comparison. For instance, compare an APC concert to a Tool concert. They both put on a cool show, and Maynard has similar flourishes in both, but the total impact of a Tool concert is much greater than APC. Sonically, APC is completely enjoyable and even fulfulling, and no one expects more than that (other than a few, erm, tools, as Alan pointed out). A Tool concert, on the other hand, is a full mind and body work out. That's not to say Tool is better hands down, though. They can each be better in different situations, moods, what have you. Sometimes you feel like a nut...
And if anyone's looking for a band to fill in the gap between APC and Tool, might I recommend a little
Truckfighters. The base is more stoner rock than prog metal (more Black Sabbath than Pink Floyd, if you will), but their albums have evolved similarly to those of Tool. The new album,
Mania has many Tool-like touches.
If that's not your thing, there's always Dredg, who are often compared favorably to Tool. However, each of their releases after their first have been too emo/girly for my tastes.
"It is not the literal past that rules us, save, possibly, in a biological sense. It is images of the past. Each new historical era mirrors itself in the picture and
active mythology of its past or of a past borrowed from other cultures. It tests its sense of identity, of regress or new achievement against that past.”
-George Steiner
Sorry Onos, I only just now got that! 
Bit slow today....
