Favourite Giles episode would be A New Man

Same, I think, and I really like his dynamic with Ethan in all the episodes they have together (though Giles would probably object to that being characterized as a BroTP, heh).

I do like Giles/Jenny, though -- but I can see your points about why you don't.

I never want Giles to do anything to betray Buffy again, Helpless was enough for me

Hear, hear! I just recently rewatched tha tepisode, and... ouch. :(