This question has been asked many times before on AB, and I've answered it quite a few times, but who cares . . .?
My absolute number one favourite sandwich has to be Stilton cheese and mango chutney on any decent sort of bread (e.g. granary). I discovered it in a London sandwich shop and I've made it many times since. Last week I spotted a jar of mango chutney on a shelf behind the counter of a local sandwich shop. I knew that they'd got Stilton, so asked if I could have my favourite sandwich. It was lovely . . and so was the next one I had to order a few minutes later ;-)
Another discovery (at the caf� serving a local auction room) is cream cheese with (crunchy) peanut butter and celery. Sounds weird, tastes great! ;-)
Chris