Lower enlisted (E-1 to Petty Officer 1st class):
Dress Blues (have the flap on the back of the top and a 13 button fly (yes, a pain to undo if you have to go, lot of sailors altered the fly with velcro)
Dress Whites (also have a flap, normal fly though; but white picks up everything)
Working Blues (Dark blue pants & long sleeve shirt, looks black)
Working Whites (White pants and short sleeve shirt)
Dungarees (bell bottom trousers, and a light blue shirt with either long or short sleeves, it's a blue & white weave called chambry (sp?); very similar to some prison uniforms, because they used to be made by prisoners)
males wear the dixie cup with all uniforms, while the females wear a combination cap (there was a black garrison cap that used to be worn with the working blues)
a command ball cap can be worn with the dungarees
Coveralls were often worn by personel doing dirty jobs
Squadrons and flight deck personel (and often supply, because they ordered the stuff in) often used a variety of pants, like the old pickle suits of the army or BDUs (in both cases, all pockets were sewn shut to prevent FOD hazards on the flight deck); sometimes coveralls were worn . a Jersey was also worn (looked more like turtlenecks), the color and markings specified by your duties, even with coveralls. when working on an aircraft (or more then a foot off the deck) crews were required to wear cranials (head & hearing protection comprised of two plastic plates with foam padding and hearing protectors held together with a skullcap) with the plates also depicting purpose and unit, on the flight deck a matching float coat was worn (automatic & manual floatation device, dye pack and a water activated strobe)
Special Operations (SEALs) wear whatever best suits the purpose. In fact, the only two items that are never concidered expendable are mini-subs and photographic film (or digital cards) containing surveillance images (there probably are more items, but nothing they can admit to).
Enlisted may also wear the dinner dress (blue or white), formal dress, or tropical dress uniforms the officers have when appropriate (formal gathering, and normally only if stated as being authorized; though there may exist exceptions)
Upper Enlisted (chiefs):
The blues change to one that looks more like a suit, as do the whites.
They loose the dungarees and gain khakis (tan in apperance, there are short and long sleeve versions)
Instead of a dixie cup, males wear a combination cap similar to the officers, but with a chiefs anchor (I think, been a while), females continue to wear their combination cap. with khakis, the cap is khaki, otherwise it's white.
Chiefs also wear flight deck gear similar to the other enlisted, and may wear coveralls if they need to.
Like the lower enlisted and petty officers, they may also wear the officers formal uniforms (they are expected to pick up the dinner or formal uniform, even though it's not required)
Blues, whites & khakis, their combination cap bears an eagle (and accouterments) over crossed anchors, at higher ranks they add "scrambled eggs" to the cap
O-3 and below are not required to wear the dress and formal uniforms, but if they expect to advance they should.
The navy is currently in transition
they have adopted a green uniform similar to the Marines for Aviation Officers (& CPOs?)
and are changing to a dress working uniform similar to that worn by Navy personel attached to a Marine unit (doing away with the working blues & whites); to begin in 2008
decided to change the working uniform (dungarees) with a blue, grey, & white digital (also 2008); an interesting note is that it was designed to hide stains that enlisted tend to acquire and it was made similar to the other digis in use in that is does not require ironing (in most cases, it's nearly impossible to really iron them)
Personally, I'd go with something similar to Marine digis (army would work) for combat forces, as the Naval troops are part of the decendants of SEALs and UDTs and the Marine forces (Master Chief would probably be concidered a SEAL, welcome to discuss this though)
Some other items to concider:
Rates and Ranks?
Ranks can be kept E-1 to E-3 are a little strange, there's one for each career field: Corpsman (medical; white on blues, black on whites), Airman (aviation; green), Fireman (damage control & mechanical fields(?); red), Constructionman (CBs; light blue/cyan), and Seaman (everything else; same as corpman). E-1 are recruits (fireman/airman/etc recruit), E-2 are apprentices, and E-3 are full fireman, corpmen whatever. If they have a rate, that may be added in front of the rank: PRAR, AMSAN, MMFR etc.
Petty officers get easy, E-4s are third classes, E-5s are second classes, E-6s are first classes. There is some variation you can use to refer to the same person - an AO second class petty officer can be called: AO2, PO2, second class, PO <name>; the prefered variations are the first and last ones.
Chiefs range from E-7 to E-9 and are Chief Petty Officers (Chiefs), Senior Chief Petty Officers (Senior Chief), and Master Chief Petty Officer (Master Chief), There is a fourth that is also an E-9, but has special duties, he's the Command Master Chief and there is only one in any command he is the enlisted representative to the unit commander (known reverently as the CMC, but never to his face, he's still Master Chief). There is also a Command Master Chief of the Navy who is the enlisted representative and advisor to the CNO and CNP (Chief of Naval Operations & Chief of Naval Personel)
Above that are the officers, but who cares about them
What's available, I can see most aviation rates combining as the Navy goes to space; PRs (Parachute Repairmen) would probably get a name change and become Armor Maintainers (AM), while airframers (AMS, AMH which are merging?) would likely roll into MM (Machinist Mate) or HT (Hull Tech)