The list of decent English quaffing ales is endless and I'm no more trying to put together an extensive archive of them than I am of Belgian beers. My most recent discovery is Fuller's ESB, a light tannic bitter with a slight tea-like flavour, reminiscent of Theakston's, though with a stronger dose of hops.
Bury St Edmunds (the BSE of the title, in case you thought I was suggesting bitter as a cure for brain disease) brewing giant Greene King make an ale which is definitely not for quaffing: their Strong Suffolk Vintage Ale. This is an almost flat, deep red beer which gave me three distinct flavour notes: caramel, smoke and toffee. It's not complex, as such, but it's definitely interesting and worth savouring.