i run a 50x34 compact with a 11/32T cassette on my cannondale 105.i can climb just about any hill here in sunny wiltshire,if you run the same set up you defo wont need a triple chainset.my 105/5800 will take up to a 32T cassette which as i said is more than ample..For the N+1. I was thinking about a triple but there are none left in the sales in my size.
The new Defty Advanced 2 with 105 and disc breaks looks good for £1400 and a 34/30 easiest gear would be ok.
For now though I'm at the Liberty Stadium to see the Ospreys beat the Dragons.