gad.. well how much are you planning on hauling, and what kind of terrain you riding over?
if you want supreme flexibility for lots of different terrains-- a triple is great-- and the gearing should come out of how much you're pulling around and what your definition of 'fast' is. if you're REALLY loaded on crazy hills- a 24/34/44 would be great-- and you'd probably do best with a long cage rear for sure. for cassettes.. well.. i guess that also depends on what you're hauling too. but chances are-- you don't need race style big rings for loaded touring
all of it comes down to needs and preferences. were it myself-- i'd stick with lower gearing, probably and 8 speed cassette, probably 11-32 and the 24/34/44 front rings. 26/650b is super nice for big fatty tires and good fender coverage and comfortable ride... also convenient tube changes.
bars... that's also preference. i'd certainly choose a brooks saddle, and likely barcon shifters.. maybe some nitto noodles. i'd go with a quill stem if possible for easy height adjustments, and i've never struggled too much with a seatpost.
look at sites like cyclofiend for inspiration! loads of amazing builds over there-- and keep in mind what the application is, and that'll shape what you put on it!