I am about ready to order my wall plates and keystone connectors. Any recommendations on brand quality or durability?
If you're doing a lot of plates or a whole house, I'd recommend sticking with the name brand ones (e.g. Leviton) because they are widely available and are likely to be around years from now, so you can get matching color/quality/good-fit-compatibility any time now or in the future. If you buy them in bulk and/or mail order the pricing is better. But when you need one - it's nice being able to pick one up at Home Depot, etc.
If you're only doing one room, though, and can use the standard colors (white/ivory), just get all the parts from the same place and you'll be fine (Monoprice)...
You can't go wrong with Monoprice keystones and plates. They are of good quality and the price can't be beat. Only downside is that Monoprice doesn't offer Decora-sized plates. For those, I've had to order from RAM Electronics.
Most keystones should fit any wall plate made for them. Leviton / Belden are probably one of the more reliable ones, I'm sure the Monoprice ones are made by one of these guys. others are right, buy from the same place.