As of today, you can buy several Capcom games, including Super Street Fighter IV Arcade Edition,  for half price on Windows Live.

Dark Void – regularly $29.99, now $14.99
Dead Rising 2 – regularly  $29.99, now $14.99
Lost Planet 2 – regularly $39.99, now $19.99
Lost Planet Colonies – regularly $29.99, now $14.99
Resident Evil 5 – regularly $19.99, now $9.99
Street Fighter IV – regularly $19.99, now $9.99
Super Street Fighter IV: Arcade Edition – regularly $39.99, now $19.99

Now go forth, brave PC gamer!