I typically have the regular suspects already named: Bombay Sapphire, Hendricks, Tanquery 10. I have tried the Sapphire East...pretty good as well.
I recently got a bottle of Bulldog with high expectations, but it was just so-so.
Monkey 47 is a favorite, but haven't seen it for sale in the US. A special treat when I get to visit the LH First Class Lounges.
For Gin & Tonic, I am more focused on the tonic water instead of the gin. Makes a huge difference in the drink. There are several high-end tonics that have appeared on the shelves. The LH FCL/T have stepped up with a better tonic. Make sure to ask for it instead of the Schweppes.