One strap shoulder Man-bags are all the rage. They are pretty practical, especially when you can’t fit your checkbook-sized wallet in tiny pockets. But in the US it looks like you’re wearing a fanny pack.
Especially true in SE Asia. I resisted the trend because it looks effeminate, like you're wearing a purse. Asian guys love them because they're super practical if you ride a motorbike or scooter tandem style. I think it works better for more masculine types to go for a bigger bag. I have a black Crumpler bicycle messenger bag (not super big, just a normal-sized bike messenger bag) and it works great for me down here.