Same here, but I use Ctrl-j. I never understood why I see everyone using Ctrl-a and Ctrl-b. Those are two very important navigations in my opinion.

not that important if you have:

    set -o vi

in your bashrc.

Better yet, use `set editing-mode vi' in your .inputrc so that bash and other readline enabled utilities default to vi-style bindings.

I am still used to <C-B> as a prefix. For splitting windows I am using <C-B>“ for the vertical split, and <C-B>_ for the horizontal split.

The lines indicate the splitting direction, and I do not have to move my fingers around that much to reach, e.g <C-B>%

I've always found the backtick (`) to be the most convenient for me. I can hit it easily with my left hand ring finger and I don't have to type backticks too much as I typically use $(command) for command substitution.

Agreed. I fell in love with Tmux from the moment I realized it used <C-b> as the prefix. Still accessible with just my left hand (especially since I map Caps Lock to Ctrl), but doesn't block a commonly-used chord.

Ctrl-a a gets you to beginning of line. My problem is that I'm so used to that combo that on the rare occasions that I'm not in a screen/tmux session, I keep putting "a"s at the start of the line.

Note that maximum-awesome is for/by the vim crowd -- who could not care less about Ctrl-A being move-beginning-of-line but do want continuity with screen's prefix-key.