I'm possibly using Eb sometimes, or maybe even F... :lol:
I aim at E, but I only use a tuner when I'm about to record something (or play with other people, which is rare nowadays)... I'd rather tune by ear if I have the time, and often I'll take my reference off a keyboard (or another guitar) instead anyway.
I use 11's on all electrics now. Years ago it used to be 10s on fenders, and when I started using gibson scales as well I found the 10s to be far too floppy. So I spent a few years with 11s on gibson and 10s on fender - they seemed to balance reasonably well.
After a long break from guitar I got a new strat, and the only spare strings I had in the box were 11s - I gave them a go and never looked back.
Heavier strings definitely sound different - personally I'd say meatier. But whether that's down to the strings themselves, or how they make me feel and therefore how I hit them, I really don't know anymore. I do know that I have to take this into account when trying a guitar in a shop - I have to remember it's going to feel and sound a lot "better" (to me) if I get it home and rip the floppy strings off it.