Personalized Uniform

A personalized uniform is a set of outfits that adhere to a general theme or style, but aren't actually identical like you'd expect uniforms to be. They'll usually be color-coordinated (either everyone wearing the same colors to tie their disparate styles together, or else having uniforms of the same style but everyone getting their own color). This is very useful for providing Distinctive Appearances—the similarities in the outfits allow you to easily identify who's part of the group and who isn't, but their differences allow you to easily identify individuals within the group.

Note that a personalized uniform must be the characters' official attire—if they're making changes to their uniforms without permission, then that's Custom Uniform. Expect to see particularly attractive characters wearing a Custom Uniform of Sexy.

Anime

 * In Naruto, all that seems to be required is that they wear a forehead protector with the symbol of their village, and even then they don't always wear it as a headband.

Comic Books

 * The government-sponsored X-Factor all shared a common color scheme, with individual variations—Madrox's full cowl and Badass Longcoat, Havok's leather jacket and headgear, Strong Guy's coke-bottle glasses, etc. Quicksilver stuck out because he kept his traditional outfit, light blue with silver lightning. Although it fits his aloof and arrogant demeanor, it belies his grudging acceptance of membership in the group of True Companions that develops.
 * In The DCU, The Legion of Super Heroes franchise has done this twice:
 * In the early issues of the "present day" Prequel comic, L.E.G.I.O.N. '89, characters wore a wide range of clothing styles reflecting culture, alien anatomy, and/or personal aesthetics, but they all shared the standard livery of black underlayer, white overgarments, and the L.E.G.I.O.N. symbol in gold. No two characters, even those in the background, ever wore quite the same outfit: despite this, they were all obviously members of the same force. Later artists got lazy and gave the rank-and-file grunts identical uniforms.
 * In the main title, the Legionnaires had always had individual costumes. However, the early 90s younger versions of the team redesigned those costumes to have unifying elements: a three-part division with a center band of contrast running down the middle, from neck to bootline, and a thick black belt with Gadget Pouches and a very prominent Legion emblem on the buckle. All of these held on through the 1994 Continuity Reboot, and the last through the 2004 "threeboot", and in the Animated Series, even Superman added it to his own classic costume.
 * The bulk of the Green Lantern Corps wear the standard bodysuit, Domino Mask, and Green Lantern Ring. The ring is the only mandatory part, as the source of their powers, and many of the more far-out members have special uniforms to accommodate their anatomy. One Green Lantern, Mogo, displays his affiliation with the Corps by rearranging his foliage into a massive green stripe around his equator with a Green Lantern symbol in the middle.

Film

 * In the Star Wars prequels, each Jedi is basically allowed to wear whatever they want, but they typically wear similar-ish robes as a show of solidarity, with adjustments for individual taste and practicality.

Literature

 * The uniforms of the Wardens in The Dresden Files consists of a grey cloak. Aside from that, they wear whatever they like.

Live-Action TV

 * Peacekeepers on Farscape: They started out with uniforms, and the lower ranking troops continued to wear uniforms, but for anyone with the rank above Senior Officer or Lieutenant the rule seemed to be "As long as it's made out of red and black leather..."

Video Games

 * In Star Trek Online one can create their own uniform out of several different pieces, styles (both from the shows and new), and colour schemes. This is even hand waived by one of the Loading Screens giving the year uniform regulations were relaxed.