Of course you pay more for the Poly than the CR and the WL, but I believe it's well worth it, for theming, location and atmosphere in the case of CR, and for location alone in the case of WL.
WL - I know the above poster had great experience with WL transportation, but I had a hard time with the boat in Oct. 2001, and many others on these boards have complained about transportation being the only drawback to WL (it is a breathtakingly beautiful resort with terrific service, great pool, etc.) Pricewise, you save a lot over the other two, and that's because it is much less convenient.
The CR is great for its proximity to MK. There's nothing else about it that's a particular WOW, unless you have a tower lagoon view. That's something special!
THE POLY!! It rules for its location on BOTH monorails (you can easily walk to TTC from ay room at the Poly, though some are closer than others - bring your stroller), its grounds are beautiful, service is great, and the theming is very lush. My family also loves the restaurants there. With a toddler, you gotta be thinkin' how can you most easily get back to your quiet room?...I'd go with Poly.
GF is beautiful and elegant, too. What the heck, you're going to WDW. What could be bad...(except for that yucky, dirty room in CR? Eew, glad we don't hear too many report like that.)