My mum is a massive fan of her Raclette grill. If you aren't familiar with said machine, its basically a little grill with small triangle frying pans onto which you cut different cheeses. You are supposed to use Raclette cheese, but we generally use any and every cheese!!
You put your little triangle pan onto the grill and your cheese cooks and melts. Then you get some Mediterranean veggies or some fresh bread or whatever you like to have melted cheese poured over, and you pour it on. It goes hard when it cools, but gosh its gorgeous!
The cheeses that work the best are those that melt easily - your cheddars and gloucesters as well as the special Raclette cheese.
However, blue cheeses like Stilton and Brie work well, and taste amazing melted. But you can use Smoked cheese, Emmenthal, or for a bit of a kick those with chillis in or mexicana.
They are all great. It doesnt work so well with Feta I find, but other than that, pretty much any cheeses are lovely. My personal favourite is the Marmite cheese bites and the seriously mature cheeses.
If you haven't tried this then you need to. It is an amazing device and melted cheese is just sublime!! :)