Actually, just tonight I let my female Haunter (lv. 45 I think she was) evolve into Gengar by trading her. She is definatley doing better now. She has a bold nature so her special att stat is AMAZING. Also, for some odd reason, she seems to be gaining more HP each level she grows than her pre-evolutionary form. So yes, I would say let her evolve into a Gengar. I can trade you if you'd like (then trade you back your Gengar obviously :P). The moves I have for mine are Dark Pulse, Shadow Ball, Dream Eater and Hypnosis. I think this is a pretty decent move set. If she is low on HP (and being a Haunter owner you should know they usually are) then I use Hypnosis and Dream Eater in a combo. I can gain full HP back from this most of the time. I have Shadow Ball as it's ghost-type move (seeing as Gengar is ghost-type :P) and I have Dark Pulse as a dark-type move (just incase I'm battling a normal-type pokemon and ghost moves have no effect on it). It just turned lv. 50 and tried to learn Nightmare, which is a move that reduces 25% of the foes maximum HP each turn if it is sleeping, but I refused seeing as I would much rather have a HP replenishing move. So, there is my advise. Take it or leave it, and if you would like to trade and trade back your Haunter to get a Gengar, feel free to PM me.
