Open, for the reasons listed by JiK. My oven has a door 'stop' that keeps it open about eight inches for broiling.

If you are setting off the smoke alarms, U R Doin it Rong! The meat shouldn't be charring/smoking, but browning nicely without any smoke coming off it. My oven has low and high broiler settings, and I use the low for most meats, and I've never had the smoke alarm go off. the toaster, however, will set off the smoke alarm now and then.