Triple to double crankset
The simple solution will probably be a longer bottom bracket. Square taper BB's come in a variety of lengths specifically for this reason.

Switching to hollowtech might work, but if your frame isn't built to that spec you could well have the same interference problems... only now you have new hollowtech BB and cranks.

This is one of those times it can be worth paying a bike shop. Not for the skill of the mechanic, but for the shelf of parts. They can try different sized BB's until they find one that fits, and all it costs you is labour and a single BB. Doing it at home you could end up with 3 or 4 BB's that are not quite right.