I just grabbed Mirror's Edge, SimCity, and both Need for Speed games for my iPad! And I agree... I would have definitely gotten Monopoly HD if it were on sale. I guess they didn't want to upset those folks who paid $9.99 as it was just released.
It looks like some other game publishers are having holiday sales too. These are what I've found so far (I should note that I'm only looking through the iPad section):
Paranorma Agency HD - 99¢
Knights of the Phantasm Castle - 99¢ (also plays on iPhone)
iBomber Defense - 99¢
Ultraviolet Dawn HD - 99¢
Project Phoenix - 99¢
Helsing's Fire HD - $1.99