Why give all alts enchanting? To DE quest items that are mostly greens? Honestly, I'd just stick with one enchanter to DE the unused blues from instance BoP's.

Here's my setup:
Paladin - Blacksmithing/Mining(soon to be Engineering)
Shaman - Herbalism/Skinning
Shaman - Alchemy/Leatherworking(soon to be Mining)
Shaman - Jewelcrafting/Leatherworking
Shaman - Enchanting/Tailoring

I'll probably drop Skinning in favor of Inscription when WotLK comes out, since I've got another 70 alt with 375 skinning.