I love all cheese as long as it's got plenty of flavour to it. (A lot of French cheeses, for example, are far too bland for me).
Keen's cheddar (from Waitrose and some Sainsbury's stores, as well as selected M&S outlets) is great:
http://www.keenscheddar.co.uk/
Danish Blue has acquired a reputation as being a bit 'naff' (probably because, back in the 1960s it was the first 'foreign' cheese that many Brits tasted, while thinking that Mateus Rosé was an example of a 'fine wine') but I'm rather fond of it.
A decent Stilton is equally good (especially when my friend leaves it to soak in Port for a few weeks!)
It's generally blue cheeses which I like best (simply because of the strength of flavour) but I'll try almost any sort of cheese.
What should cheese be served with? Either more cheese (and then yet more cheese!) or simply with cream crackers (which are vastly preferable to posh 'biscuits for cheese').