105 is a good basic set up but the new outboard bearing crankset looks "pants" (I've got one) so why not mix n match,
The rear shifter must match the shift lever but other than that you can fit just about anything as budget and time allow. The only times I have changed a front shifter is when they have been a cheap steel one so keep the one you have fitted, then pick the crank you like that looks the best on your bike (and works the best) then upgrade other parts whenever you find them on offer.
I would now avoid Campagnolo as having given the old credit card a battering when I built up a lovely frame (653 tubing, unknown make, no frame number,but some lovely details like a three slot drain and brazed on cable guides on the bottom bracket, internally routed rear brake cable run & lovely long pointed lugs) I find that the rear shifter will not stay in adjustment despite having 3 separate adjustment points on the cable. This bike always gets admiring comments but is a pain to ride with all the clonks & rattles from the back end (though at least 1 of the adjusters is on the bar end shifter) which, having been used to the sweet click of Shimano shifting, I find disappointing. Cost me well over a grand, it all matches and I only did it cos it had a campy headset and seatpost when I was sold it.