I was wondering if anyone had any suggestions concerning the combination of the DPR 2005 with the 422s. I assume the DPR is powerful enough, but in terms of sound quality for music (especially music) and movies, will this work? Also, the DPR2005 is a 7.1 receiver, but can I still get quality surround sound with the 422 5.1 system? Ideally, Id like to upgrade to a 7.1 eventually, but I'll be working with the 422 5.1 in the mean time.

The 422 system is impressive for both it's size and price!  I heard it at the HE show in NYC last year and I own a pair of the 422's for a living room system at home. 

The H/K mates very well with Aperion IMO.  I used an AVR230 to drive 522PT's with good results, so you should be good.  If the 422's are all you can afford, you still won't be dissapointed.  Moving up the line gains you benefits, but the beauty with Aperion is that your 422's are worth the same as the day you bought them up to a year later if you want to move to the 5 series or even 6's?  Possibly moving two of your 422's to the 6th and 7th channel duties?  You might also find that 7.1 isn't even needed.  I've had HT's set up in two differenct spaces, a very wide space that benefitted from the 6th and 7th channels and another where anything above 5.1 would have been overkill and possibly even distracting.