Some small vim tweaks I've recently been using myself that I find very nice:
nmap :write
cabbrev w nope
Re-map enter to save the file. If you try to do a :w it will yell at you until you take out the cabbrev so you can retrain your muscle memory. Took me about a day to retrain.
let g:EasyMotion_leader_key = ';'
nmap s ;w
nmap S ;b
Remap s and S to be easymotion forward and backward. I never use s, since it's largely a redundant command, and didn't like having to do a two key command for easymotion. (You can set the leader key to whatever here, the nmap's are the important part.)
noremap h
noremap l
noremap j
noremap k
Move between panes with motion keys with control held down.
Also the YouCompleteMe plugin got some HN airtime but it really needs to get more. It's amazing.
http://valloric.github.com/YouCompleteMe/
And as others have mentioned using vim inside of tmux is very nice. It's especially helpful to remap the entire tmux keymap to be vim-like.
Also, does anyone have any suggestions for what to re-map Space to? I am amazed Enter and Space in command mode both do relatively useless things. Remapping space to page down is OK but I use ctrl-f/b which is just as fast imho.