Mark Zuckerberg

Even when meeting President Obama, Zuck still stuck to jeans, though he did ditch the hoodie and NorthFace apparel for a sport jacket and tie. Small steps, right? Photo credit: Elaine Chan and Priscilla Chan

Jobs’ standard attire consisted of wire-frame glasses, a black turtleneck, blue jeans and tennis shoes—a look that became nearly as iconic as Apple’s sleek products. Photo credit: mylerdude

With sweaters, khakis and ill-fitting, neutral-colored button downs (often sans tie), Gates often looked like the dad next door—albeit one of the richest and most powerful in the world. Photo credit: blind_justice

The look may be subdued—dark suit, white or light-blue collared shirt, no tie (top button left free, of course) and sleeves rolled up, but it is certainly consistent, and speaks to the casual power of the CEO of the world’s largest online retail store, Amazon. Photo credit: James Duncan Davidson

With his geek-chic glasses, unkempt hair, ironic T-shirts and … um, that’s about it, really … the CEO of meme powerhouse The Cheezburger Network is the height of hipster executive fashion, if that’s a thing.Photo credit: Sage Ross

The founder of popular social networking sites Dodgeball and Foursquare takes a page out of Zuck’s fashion playbook with a predilection toward wrinkled jeans, hoodies and T-shirts. Comb your hair, Dennis. Photo credit: Jonathan Crowley

The founder of Craigslist has a decidedly low-key approach to running his business, and that extends to his attire, which fuses berets, scarves, baggy jeans and geeky glasses. Photo credit: Sierra Communications

Where do we begin? A former Google employee, Twitter investor, and founder and principal of Lowercase Capital has a penchant for loud, embroidered cowboy shirts—this is a rather subdued example. Photo credit: Doc Searles

Apple’s new CEO brings a certain casual suaveness that feels a step up from a black turtleneck, with dark button-down shirts and smart wire-frame glasses.

One of the brilliant minds of the 20th century, Einstein knew how to mix the rumpled professor look and infuse it with an amorphous charisma and a seriously wild hairstyle.