Next lens

Hi,

I won't ask for "What should I buy next", but I want to gather some ideas and experiences.

I am looking for my next lens and let me give you the facts:

60D
Sigma 30mm 1.4
Canon 15-85mmm
Tamron 70-300mm VC
Canon 50mm 1.8 (not used for years)
Speedlite 430EX II

I am shooting family indoors/outdoors. Camping, beach, sports and lots of traveling.

The Tamron, bought with my old Rebel T2i, performs surprisingly well outdoors and in bright conditions (especially when stepped down). The reach is all right and I don't need a longer zoom. The 15-85 is amazing for travelling, but same here, when it is getting dark or indoors I need the flash. The Sigma is for indoors and produces stunning pics, though it is not easy to work with it. What (I think) I am missing is a low-light zoom or prime with a longer reach. I was thinking getting a 70-200 2.8, but the weight and price scares me. I have considered the Sigma 70-200 2.8DG, Canon 70-200 f/4, f/4IS,2.8, 2.8IS and the 2.8IS II (in case I win the lottery tomorrow).

An alternative would be the 135l 2.0, but I am afraid that limits me too much regarding the fixed 135mm.

Another idea would be the 85L for some nice portrait shots of my kids. Choices, choices, choices...

I went through my photos:

The majority of my pics are under 100mm with peeks on 15,30,50,70 and 85mm. That let me think if I really need a 70-200. But then again, those numbers come from the usage of my favorite lens. I just don't carry the Tamron too often.