Use Guinness/real ale in there, as Dolph says a whole bottle. Try adding something a bit different to the sauce like mushroom ketchup or even a little nutmeg as well as mixed herbs.
To make it a little different when serving: thickly slice part of a a french stick. Liberally spread one side of each slice with dijon/french mustard. 15 minutes before the end of cooking take the lid off the stew/casserole, place the bread mustard side up on top of the stew and bake in the oven for 15 mins. When it's ready the gravy will have soaked into the bottom of the bread and the top of the bread will be all mustardy and crunchy....yum!