I decided to make an Inquisitor with terminator armour and psycannon for use with my imperial guard (with prescience obviously!). Sadly he and his ogryn bodyguards walked into a pheonix lord in thier first game. But I have high hopes for him in future. I really like the warspear bodies (the spears and heads are pretty awful though) and the sorcerer head which is designed for a marine/terminator body looks better on this body I think (it helps avoid the giant head issues that some 28mm models can have).
Parts:
Blighted Ogrun Warspear
Chaos Sorcerer Head (with some greenstuff to give him a neck)
Minotaur kit axe (with some greenstuff on the handle)
Epic
40k weapon (plasma blastgun maybe?)