For professions, cooking and archaeology are the only things left. (without untraining a primary profession and learning a new one.)
Archaeology is a time sink pure and simple. It has some neat stuff if have the patience to dedicate days or weeks to it but you could also go your entire WoW career leaving it untrained and never miss it. (Maxed archaeologist speaking from experience here.)
Cooking is relatively easy, though somewhat annoying and time consuming as mats can be annoying to get and you hit blocks where you need daily tokens at wrath and cata levels. Cooking is useful though as you can make your own buff food.
You could also look at hobbies that don't involve professions. You could take up mount or non-combat pet collecting or rep grinding or something too.
75 Rabbit/75 Sheep/75 Coeurl/75 Eft/75 Raptor/75 Hippogryph/75 Puk
75 Scorpion/75 Wamoura/75 Pixie/75 Peiste/64 Sabotender
51 Bird/41 Mandragora/40 Bee/37 Crawler/37 Bat
Items no one cares about: O
Missions no one cares about: O
Crafts no one cares about: O