Leah,
For a garden view room, I always like Tokelau. Whatever direction you face, you get a more secluded, serene jungle setting. One long side faces one of the quiet pools, the other faces just paths and well-maintained vegetation. The central location is great, because you are not far from the pool, main building, and monorail. But you are also walking distance to the Ticket and Transportation Center, which gets you to the Epcot monorail more quickly as well.
If you have the chance to request backup buildings as well, they would be Niue and Tahiti.
I am going in September 2010 for a big family vacation, and that is what I have requested, for what it is worth.
Samoa is nice too, I just like having a bit of distance from the main pool, if I can get it. Of course if you get a room facing away from the pool, you are going to be fine too!
I am glad to answer any other question about the Polynesian that you may have! Just ask!
You might also visit the unofficial Polynesian fan site,
www.tikimanpages.com/tiki. I love this site to get in the Polynesian mood!
Have a magical vacation!