Well, I've eaten at quite a few curry houses in my time. And there are a couple that are worthy of mention.

The latest one I'm liking is 4500 from Delhi. The chicken Chettinad is my favourite right now. And they have an amazing lunch buffet.

The Brunel Raj in Clifton Village is very good.
As is the Lal Jomi in Redland.

I'm sure there are lots of other good ones, but these are the ones that I've enjoyed.

Oh, and if you're in Milton Keynes, check out The Grange in Grange Farm.