Hotels about a 10-12 minute walk from the dome. Quite safe especially with the game time traffic.
There's probably 20-30 (at least) restaurants/bars within a 10 minute walk as well. Safety won't be an issue at all unless you're turning down a side alley at 4am. But I wouldn't advise that anywhere.
Here's a good place that lists a lot of the restaurants in the downtown area. The event will be over by the game but still gives you an idea.
http://www.atlantadowntown.com/darw/about.html
And some more info....
http://www.atlantadowntown.com/HavingFun.asp
The Ellis is brand new, the rooms are a bit on the small side (think NYC hotel vs Las Vegas) but are very nicely appointed. I wouldn't try and put 4 adults in there but 2 adults would be perfect.