Interesting that a lot of the Trek fans I talk to online who are in some way tied to a military or other all love Jellico, and consider him to be the best commanding officer portrayed on TNG, or possibly even on any Trek series.
Ironically, as a civilian through-and-through, I had not quite recognised this when I first saw Chain of Command, but now looking back I see what they are getting at.
But then, a lot of the military people may not like the idea of turning Galaxy-class ships into mobile towns (with families aboard) - though to be fair, Picard was against the idea at the beginning, and never quite warmed up to it that much.
Plus, it's hard to argue when what would seemingly be a logical course of action in many of the dangerous missions the D found itself in (separate the saucer and park it over some out-of-the-way world, or hide it in an asteroid belt at low power, while using the stardrive section to go do the fighting) was quite often ignored.
(For example, would it have been safer for the families aboard in BoBW to transfer command and let the stardrive go and draw the Borg cube away from that nebula? They were clearly after Picard himself, after all...)
But my personal fave guest CO?
Hmm...
I can't really think of one in particular.
Sorry.