Hi and welcome from Long Island!!!
I stayed at the Contemporary only once-- after high school graduation in the 70's.
But we stayed at the Poly twice, and LOVED it. It's a tranquil countepoint to the frenetic craziness of the parks. It really is lovely. And the location is incredible; the MK monorail is right there, and the TTC (where you can get the Epcot monorail) is a short walk. We stayed in Tokelau both times, and the location was wonderful; a short walk to the TTC, a tiny bit longer to the main Monorail, and a bit longer to the Volcano pool, though the quiet pool was right next to our building. We also requested, and got both times, a full balcony.
We've since tried the Beach Club, and will be staying at the adjacent Yacht Club in a few weeks. Its location, steps from Epcot and a short boat ride from Hollywood Studios, is also incredible. And the swimming complex, Stormalong Bay, is amazing!!
For my family, the pool is key. (In fact, that's the prime reason we've never stayed at the Contemporary. The pool just does nothing for me.) My kids are total water rats. And we stop touring every single day at about lunchtime, and head back to the resort for a few hours of swimming. It's wonderful family time, and the parks tend to be too hot and busy and crowded and cranky for my taste then anyway.
OK, in other stuff: do the numbers and decide on whether or not you want the meal plan. We love it, although lots of people here on the Disboards don't. It DOES safe money for my family. And, equally important, it saves sanity. I love knowing that our meals are all prepaid.
One more thing: once you know you're going, start collecting Disney Gift Cards. When we're planning a trip, we get them for every occasion, from Birthdays to Easter to Mother's and Father's Day. You'll be amazed at how fast those $25 gift cards morph into a LOT of money saved for souvineers.