Other:
GAME or other high-street retailers where possible, though the price difference over online goods is sometimes a factor.. which pushes me to use Impulse instead.
'Avoid Steam wherever possible, since Impulse got big enough to be able to have most everything Steam does and insist all their own products be DRM free, and everything else run without needing their client >.>
I wish I'd adopted that policy before buying Recettear, though. And I wish Impulse would hurry and implement their overlay in non-Impulse games, too - it has a couple of flaws, but it's really nice.