Let alone Harman Kardon. He's choosing between Marantz and Yamaha. So be it.
In my opinion, go with the Marantz. But JMO_PWR had a great point on saving your big bugs and go for the 7500. With the 5500, you're gonna run out of power in no time. 7500's headroom is huge and I feel you'll never have to amp it later. I looked at this unit yesterday and I could have it for 1400 CAD. Pretty impressed.
And if you want to widen your views a bit, go and have just a quick look at NAD
(T753). Music's awesome with that one. A little better than Marantz in sound reproduction. About the same price as well (7500-T753 --> 1400 CAD)
Hint: Test your system on 2-channel music. If it sounds good, it'll go along with movies.
What speakers are your driving?