Anothe vote for Simon’s summary of High St. It’s one of those ‘rites de passage’ type rides especially if you do it in poor weather! To be honest, the ride along the top on High St itself is a little underwhelming. It’s hardly technical nor is it particularly fast until the final descent off High St down towards Howtown. But, as Simon says, the bridleway that takes you from Sandwick, tracking along the side of Ullswwater, back to Patterdale, has to be one of the very best bit of singletrack in the UK. It really is awesome.
Surrey Hills is a completely different sort of riding to Peak/Lake District and Scotland. I can understand why Richc wouldn’t rate it but you can have as much fun playing in the woods as you can coming down off Skidaw. It just doesn’t have that ‘big mountain’ feel to it.