Eastern half of W2 and the outward bit of Skyline, which despite what most people seem to think I quite enjoyed after being bashed around for the past few hours, though lots of it was under water.
Are you going to take a look at Blue Scar and Penhydd at the Afan Argoed center? Blue Scar is particularly good for rigid bikes and hardtails, a lot smoother but still really good fun.
Which trails did you do?