My preferred gin depends much on the cocktail.

Martin Miller's is my current favorite for most cocktails and straight up martinis. It's heavy on the floral and easy on the juniper.

209 is second for martinis, though it has quite a bit more juniper.

I also have a bottle of Cascade Mountain in the house but it has such a strong juniper flavor that I have yet to find a proper use for it. (This is a micro distilled gin from Bend, Oregon).

For G&T, Tanqueray is probably the best.

I've also tried Bulldog but find it to be a bit too bland, almost like vodka.

Hendricks and Bombay Saphire are fine but I like Martin Miller's much more.