Karl, the 18650 cells from e-lectronics are very nice for low cost, but they still have the PCB on the negative end (tailcap spring will chew the board away).
The Pila branded cells, and the new version AW cells<-----pretty tricky ehh...;) have a steel cap on the neg side to alleviate the tailcap spring problem (I'm not sure if all sizes of the AW cells have the steel bottom?) Check AW's thread.
Anyway...I think they're all great choices, I have some of each...except the newer version AW cell, I may have to order some just to satisfy my curiosity...
I hope this helps,
TB