I don't know how recently you bought the Panasonic Blu-ray player, but, if possible, I would return it and get the 35 instead of the 55. There is no difference between the two besides the 7.1 analog outputs on the 55 and you won't be needing them with whatever receiver you go with (assuming you will still be choosing between the two receivers you mentioned). I'm not sure how they decided 7.1 analog inputs were worth an extra $100 - my guess is that they are trying to get people to pay more through a little trickery. That is, 55 is a higher number than 35 so it must be better.
As far as which receiver to go with, personal preference counts for a lot when looking at mid to high end options. You will likely be happy with either as long as it has the inputs/outputs you require. It usually comes down to personal preferences on how it operates and only you know what you like, so you need to do your own homework. Going through the user manuals online is a good way to do this if you can't physically play with them in a store.
