I prefer a little bit lighter butyl tubes, just whatever I find on sale so it works out the same price or only a dollar more than generic tubes. It's usually Michelin, Kenda, or Maxxis tubes weighing between 65 to 85 grams in a 700x19-25 size presta valve.

To be entirely honest, I'm not sure I can tell the difference between these lighter butyl tubes over the generic 100+/- gram tubes. I can feel a difference between these and those crazy thick flat resistant tubes though.

Edited to add: The tubes play almost no factor in the flats I get. Every flat I get is random from road debris, so no brand has been better or worse. I've only snake bit a tube once in my life, and that was not from a pot hole but from not clearing the rear wheel when hopping up a curb.