Horseware would definitely be my fav
Horseware is the best for sure, but I've also used Weatherbeeta with wonderful results! They used to have issues with breathability, but I've had no issues with the Orican Freestyle
Lamicell is also a good brand, a good bargain but it depends on what you're going to do with (outside or in stables), but I agree with Rebecca Horseware are the best ones!
Horseware are the best quality rugs, and Dy'on are the best sized :)