I love cheese - it truly is one of the most awesome foodstuffs around. And you're so right about toasted sandwiches tasting better. The cruddiest sandwich becomes quite delicious once it's toasted!

Cheeses I particularly love are brie (especially in a toasted sandwich - it's just perfect) and fetta. Fetta actually melts quite well, too - try putting it on the base of a pizza or a quiche. Havarti is a nice, squishy sort of cheese, but you have to find a nice one. Some of them are incredibly boring.