Leto... the addidas gym bag. Wow. I'd forgotten those things. Doing some cursory googling and I can't find a picture of one. I just remember they were all the rage but were highly impractical.
My love of the shoulder bag comes directly from Raiders of the Lost Arc. I wanted a leather bag just like Indiana's. I settled for something like this and used it all through University:
When I was a bike courier I used a messenger bag that looked like this:
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Now I use a backpack because it distributes the weight of my laptop evenly across my back. When I don't have to worry about my laptop I still use a shoulder bag.
And I agree with Hal... I hate to carry shit in my pockets. I didn't mind when I was in Canada and would almost always have a coat or a jacket. But now that I rarely have to wear a jacket I don't want to have my pockets stuffed with phones, notebooks, keys, wallet, etc.