compact beats a triple anyday... the weight penalty of a triple makes no sense anymore now compacts are so readily available.
105 is a good groupset... yes, its not got the gear change slickness, or ultra light weight of an Ultegra or Dura Ace system, but its a fraction of the cost, and for the vast majority of riders, the shifting performance difference is so little that its not noticeable... I had 105 on my winter bike (until it got nicked) and it was abused beyond beliefe, and never missed a beat. Its a worthwhile step up from Tiagra.
I agree with your LBS on the discs... they are heavy... and unless you plan on doing losts of very high speed braking attempts on steep hills in foul weather, then the braking benefit isn't worth it... plus they make things like puncture repairs at the road side just a little bit harder... spend the extra on better wheels and good tyres instead... you'll get a lot more benefit from them.