Congratulations! The Polynesian is one of my favorite resorts and I am sure that you will have a fantastic time there!
These two links will give you ALL the information you could possibly need:
http://www.disboards.com/showthread.php?t=2863058
http://www.tikimanpages.com/tiki/
What type of room are you booked in? Garden View? Lagoon View? Club Level? I would be happy to share my personal preferences once I know which room category you will be in.
ETA: Just realized that you are just considering the Polynesian and probably have not booked anything yet, so never mind! Tikiman's website gives a good overview of the various longhouses (pros/cons of each) and their views, so I would definitely check there first. Personally, I think that the garden views at the Poly are great and allow you to save $. My personal favorite garden view rooms are those in Samoa facing the volcano pool and pretty much any garden view room in Tokelau closer to Seven Seas Lagoon. If you want to splurge for a castle view, I have read great things about Tahiti.
I think that the Poly would be very romantic for the two of you. The atmosphere is so peaceful at night with the torches lit up throughout the grounds and the hammocks on the beach facing the MK/lagoon. Plus, the restaurants are really great (Kona Cafe and 'Ohana... yum) and Captain Cook's for quick service is great too. The location cannot be beat since you have easy access to the MK and monorail resorts via the monorail, plus the ability to walk to the TTC to hop on a monorail to EPCOT. The Polynesian's proximity to the TTC makes it, in my opinion, the most conveniently located MK resort. I say go for it!
