Its difficult to say, not knowing your fitness level or riding style but I have been using a Stronglight Z-Light compact double 34-48 with a shimano 9 speed 12-25 cassette and it gives me a good range of gears, not too much overlap, with some nice low gears as well. I'm 80kg's and like to ride at about 90rpm and it works good for me.
One real advantage is there isn't that loss of face when you drop it into the granny gear.....cos nobody knows you are on a compact!
Also means a shorter chain, lighter chainset and all round simpler setup than a triple. However I do have a triple on my pure training/touring bike and it works fine as well.
With a compact, you could have 1:1 gearing (34/34) by using an XTR rear derailleur and 34 cassette. With a triple, you could go 30/27 or 29 and still keep to road derailleurs.
Compact and triple are both popular around here. I prefer the triple: the 39 and 53 rings and 12-25 cassette for the fast club pack rides, plus a whole set of tighter climbing gears with the 30 ring.
Looking at the profile on the website, I'd estimate you've got at least 3500 meters of climbing over the 178km stage. Assume there will be some long sections at 10% gradient or higher in all this climbing. If this is your first time on a big mountain event, I'd be conservative and carry as low as gear as possible. I'll bet a lot of people finish wishing they had brought lower gears to this party!