Depends what the group is like.
Brunswick St is good for food and has a real atmosphere around the bars and clubs on Friday and Saturday and you'll almost always find live music. A bit like Newtown if you're into that sorta thing. Vegie Bar restaurant rocks for cheapish, absolutely brilliant food and drinks but is usually packed and they make you sit out the back at the bar until tables free up.
St Kilda isn't bad in the night either, a bit like a quieter Cross. Food isn't much of a problem anywhere in Melbourne, it's cheaper and better than Sydney food-wise.