Not sure if it counts as a brand but Wear Buses I thought was a good one. I say that mainly due to the memories of Going to Newcastle from Hartlepool on the X5 as a child. In fact I think that was the original wear Express service before it was brought back later for the X6 and X7 services. Another one I liked was East Durham. It said what area the services where for and the darts where perfect for it.

Ones I hate are indigo. It is just lazy as a brand name has no point to it and certainly does nothing to help get people onto the services.
Another one I hate and it might be controversial is X lines. To the ordinary person it will mean nothing. The name just sounds stupid. If they wanted a single brand name for the Express Services then they should have just brought back the Go Xpress name.