git & less/vim

[Brian Ericson]

Anyone know how to get git working properly with less and vim?  
Specifically:

* less does not "clear" (revert) the screen properly after commands like 
"git log" and "git diff"
* vim isn't using the git extensions/file types for commands like "git 
commit"

Both of these work properly in Gentoo (and vim -- but not less -- works 
properly in Ubuntu), but it's not obvious to me what's different between 
the distros to account for the differing behavior...