Boxer Assistant: Jamba, absolutely

Bar Replacement: I have yet to see the need. I liked Bartender 3, nothing else was better than Blizzard's IMO.

Map Replacement: Other than Atlas for instances, none. Carbonite doesn't do enough to justify having it with QH, and can't replace it.

Bag Replacement: EngBags (Takes a little setup but is extremely powerful, sorts inventory for you!)

Quest Assist: Questhelper, TomTom, Tourguide, AutoItemStartQuest, (opens that quest pickup right away so you know to get one on your alts!), MobMap, Overachiever

Party Frames: Pitbull

Others: TitanBar (great info, gets buttons off your mini map), VanasKoS (track who ganked you so you can get revenge when you are less than 10 levels under them), SuperDuperMacro (macro share and longer macros), Smartbuff (set one hotkey and spam to get your toons to cast all thier buffs!), Pawn (set your scales to help you pick your gear [lot of setup]), GFW_FeedOMatic (feed your pets with one hotkey!), BadBoy (auto report spam on goldsellers), AGT (Goblin therapist for those annoying whisperers), Auctioneer (duh!), Enchantrix (help with the D/E of crap you make with your other toons), Recount (damage meter, can tell who isn't keeping up or if someone isn't doing anything lol), OpenAll (opens all your mail with one click)