Swan & Dolphin, if you catch the right time of year (Too expensive much of the time)
They just added a 3rd BONVOY property across the street next to the mini-golf (Swan Reserve)
I've heard good things about Bonnet Creek.
We have stayed at the Sheraton Vistana Resort, The Drury (near USO, not the newest one),
and at Cabana Bay Beach Resort at USO.
I really liked the CBBR; it had 2 great pool areas, a large dining/shopping/workout area, and some interesting old vehicles on display out front. If you're a Universal Studios fan, it's probably the furthest walk to USO of all their hotels.
If the pricing is not an issue, I would go with Swan/Dolphin. The large pool with the waterfall/alcove is an awesome place on a warm night, and being on Crescent Lake is always a bonus if you're EPCOT/DHS fans, as we are.
Pricing can be much higher there, however, and they tack on huge daily Parking/Entertainment surcharges, which can make it a lot less apppealing.