We're primarily influenced by the cost, size of beds (tall DH needs queen-size or his feet hang off the end), atmosphere, and proximity to the parks. Of course, "who is going" and our desire to try new places are also factors. When it was just the two of us and there was a good discount at Coronado Springs (bringing it down to the equivalent of a value resort rack rate), we stayed there and enjoyed the queen-size beds and beautifully-themed main pool, and strolling hand-in-hand around the expansive resort.
When bringing the kids for the first time (and also planning to visit Downtown Disney for the first time), the Alligator Bayou section of PORS, with its Murphy beds and subtle "Princess and the Frog" theming, and the Sassagoula River cruise to DTD, beckoned. We also traveled during a lower pricing season and there was a discount offered (15%, but not available for standard rooms - we had to upgrade to garden view to get it and thus only saved about $120, but as I said to our travel agent, "$120 is better than a stick in the eye").
On our next trip, we'll be traveling with the kids, and also my father and my aunt, who has never been to Disney World (or even to Florida) before, and likely won't ever get the chance to come back. We also learned from our last trip that proximity to the Magic Kingdom is #1 on the kids' list of priorities (and, frankly, ours too). As such, we'll be renting DVC points and staying in a 2-bedroom villa at Wilderness Lodge (the points rental translates to over 40% off of rack rate for the same villa). It's a splurge, but we want to stay together and be able to spend lots of quality family time, and we know we won't get a chance to do this one again.
Next on our "resort hit list" for the next several years: driving to WDW and staying in FW in our own secondhand pop-up camper (which we have yet to purchase, LOL!); renting DVC points and staying in a studio at Bay Lake Tower, Boardwalk or Beach Club, and staying at CBR (if they ever refurbish and upgrade to queen beds). It's certainly exciting to ponder the options!