to get some nice colorized output:
git config –global color.status auto
git config –global color.diff auto
git config –global color.branch auto

Add all changed, but not already staged files, to and remove all deleted files from the index:
git config –global alias.addrm ‘!addremove() { git add -u . ; git add . ; }; addremove’

Some aliases I use all the time:
git config –global alias.pa ‘add –patch’
git config –global alias.ia ‘add –interactive’
git config –global alias.staged ‘diff –cached’ (Shows all staged changes)

Other useful aliases:

Undo the last commit:
git config –global alias.undo ‘reset –hard HEAD@{1}’

Retrack a branch to a different remote branch, see http://gist.github.com/29095:
git config –global alias.retrack ‘!retrack() { git config “branch.$1.remote” $(dirname “$2″); git config “branch.$1.merge” “refs/heads/$(basename “$2″)”; }; retrack’

Useful command you may not already know:
git whatchanged: Shows a log + differences that each commit introduce
git stash (|list|apply|clear|pop): Allows you to stash away changes in your current working directory for later. See manpage for more info.

I do it on a per-repository basis because I have some projects where I cannot set core.safecrlf, for example projects where I use auto-generated ressource files in Visual Studio (they are generated with LF only).

My default .gitignore for Visual C# projects is:
bin
obj
*.user
*.suo
*.ncb
Thumbs.db

(Where *.ncb is for projects including C++ projects). Sorry, I primarily develop C# at the moment, therefore I have no set for real C++ projects and solutions at the moment.

Hope this helps!

Best regards,
Martin