Basic drivetrain queries for the roadies...

1. one of the key decisions appears to be the choice between double and triple chainsets, and compact or standard. is this just preference? when might you use each? this is a mystery to me though probably very straightforward indeed.
   
2. if i were looking to build a versatile audax type bike for both short weekend rides but also longer tours and centuries, what might a standard gearing be for the two or three chainrings? and what about the cassette?
   
3. i was assuming 10-speed is the way to go these days for this type of riding. what are the other key decisions when speccing the drivetrain?
   
4. finally, i've been lusting after an alloy centaur group, would this be ill-advised? could i go lower or should i try and fork out for chorus? i'm very interested in learning about shimano also, but for this particular build i'd like to go for campagnolo for a number of (frivolous) reasons.
   
   

i realise there are other forums for this but i like you lot and trust your opinions. oh and thanks for any help.

I only run standard chainsets. Why? Because it lets me laugh at riders using Triples and Compacts. Not the most sensible choice but I'm happy with it :)
Think about where you are likely to be riding. Long rides over big mountains with heavy loads means a triple would be fantastic. I've not yet come across a hill I couldn't climb in 39/26 so, thus far I've never needed the lower gearing provided by a Compact. Some people do appreciate this gearing though, for sure. Quite a few people were running Compact with a large rear sprocket and still struggling on the climbs in Ireland.

39/53 is standard double gearing.
Triples are more around the 30-40-50 mark.
Compacts are around 50/30?
Cassettes are 11-21, 12-23, 12-25, 12-26, 12-27 and a bunch of other variations

I've got 9 and 10 speed bikes. They both work. You just need to remember to use the correct spacers when swapping wheels and cassettes around. I'd choose based on cost. 9spd won't disappear for a while yet so probably offers some bargains.

Campag is evil. Never buy Campag.

Job done. :)