For standard tuned 6 string, a set of 10-46 Ernie Ball's
For tuned down to drop C - 10-52's
And for anything lower, 12-56's, and at the moment I have a 72 bass string on my guitar tuned down to F# like a 8 string
Currently 10.5-15-21w-32-44-59 in C-standard on a 25.5" 6-string (I keep thinning out the top and beefing up the bottom, though I think I'll draw the line in both departments here )
For years I used 10-52 on my 6string with Eb tuning and when I got my 7string (schecter blackjack) I would get a 70 for the low Bb.
For a while now I've been trying a different, kinda weird, combination though... 09-11-16-26-36-52-70. The first 5 strings are from a regular 9-46 set and I get separately a 52 and 70 for the last 2. So far I find it really comfortable for both solos and rhythm. The 10-52 are a little too hard on a 26.5" scale guitar for solos with a lot of bends.