not to beat a "dead" horse but is safe to say that
1. torque is the engines ability to do work i.e. the ability to turn the drive shaft and hence the wheels

2. and HP is a reflection of how "quickly" the engine can do this work.

For example: is an engine has a 300ft/lb of torque from 1500rpm to 6000rpm, as the rpm rises the engine can do its work/torque quicker.
Is my analogy on target?

Also for a given torgue/hp curve where does the tranny gearing paly a role?

Although the popular press is always talking about HP, wouldnt it be more useful to talk about torque?