>>3364496If I'm only going out for the day I use pic related for urban environments. Some bubblewrap around the bottom for protection. Plenty of room for a body, an extra lens, sammiches and pop. Enough room for a bit of shopping on the way home too.
I'll take a Lowpro backpack for times when I want more gear or need to "hike" but the shopping bag method works mostly.
Protip: Don't hold a shopping bag by the handles. Grab the upper portion like a sack. This further implies that nothing of worth is contained within.