I found my self often diff recent 10 changes in my git/svk repo: so Here's a few git diff aliases that I used (in ~/.gitconfig):

[alias]
    up = pull --rebase
    st = status
    ci = commit
    co = checkout
    br = branch
    di = diff
    d1 = diff HEAD^
    d2 = diff HEAD^^
    d3 = diff HEAD^^^
    d4 = diff HEAD^^^^
    d5 = diff HEAD^^^^^
    cia = commit -a
    lol = log --pretty=oneline
    d10 = diff HEAD^^^^^^^^^^
    last = cat-file commit HEAD