Running all over the city every day keeps me pretty busy, but also makes carrying everything I need a rather difficult task. I've had many different bags that have taken more from here to there --duffles, messengers, backpacks, even fanny packs (just kidding)-- but there's only been one format that finally proved to be the best for me.
My leather tote bag from Roots probably sees more action than any other staple in my wardrobe: I use it all the time, and I would hardly be able to function without it. It's nice and deep, so it allows me to stuff it full of whatever I might need. There's enough room for a computer, gym shoes, a jacket, or work files. The extra-long straps also make it easy to toss over my shoulder when I'm tired of carrying it. Besides, the gorgeous brown leather only gets better with age, so it's worth the investment.