That's a tough one to answer because so much of a string choice is subjective.

I've used, almost exclusively for the past ~25 years, Ernie Ball Super Slinky - the RPS version when they're in stock.
RPS 9 Super Slinky

Lately, though, I've switched to the 9-46 Pure Nickel Slinky's...
Pure Nickel 9-46

I quite like them as they darken the too-bright sound on my new Strat a little bit. They also have a nice tight low end.