A disclaimer-- I do not claim to own any of these images! I got many of them from this great website and resource for Star Trek technology research- www.ex-astris-scientia.org.
U.S.S. Enterprise NCC-1701 (TOS)
First, let's take a look at the original, shall we? Matt Jefferies' design for the bridge of the U.S.S. Enterprise is very impressive! Using colorful lights that contrast against the shiny black consoles and bold red accents, he made this an exciting and colorful look at the future! In fact, this original design has been used by the US military to plan special situation rooms and control centers. The commander has a raised center seat that swivels giving him/her an unobstructed view of all the surrounding monitors and work stations. At the front (not seen in this illustration) is the main viewer - like a big screen TV. This was an improvement on the original concept that called for a large window in the front of the bridge. This window idea would later be used in the JJ Abrams universe. Verdict: A- I love this bridge! It was the inspiration for so much... but the design has been improved upon over the years.
More after the jump...
U.S.S. Enterprise NCC 1701 - Refit (movies 1-3)
When the folks at Paramount decided to make a second Star Trek TV show (mainly to capitalize on the success of the rival Star Wars) they brought in new fresh ideas for the look of the show. This new show, which was to be called "Star Trek Phase II" included a whole new "refit" USS Enterprise and a new swank 70's looking main bridge! The concept here (seen here to the left) is much brighter and larger than the original bridge. Also, the captain's chair looks much more comfy and 70's futuristic! But the main layout is an obvious homage to Jefferies' original design. 
Of course, Star Trek Phase II was scrapped and developed into a feature film called Star Trek: The Motion Picture. Much of the designs done for the show carried over to the film. You can see here that the bridge we ended up with is similar to the concept art with some major differences like the captain's chair is much less comfy looking! One of things that bugs me the most about this bridge is the stations where there is no seat. Granted, the standing desk is pretty popular now-a-days in ergonomic friendly office design, but I'd think that would be a bit dangerous on a starship that will inevitably experience turbulence, right? The seats now feature arm rests that fold down over the legs, acting a bit like seat belts. But that's no help to the poor crewman standing at the environmental controls station! Verdict: C It looked cool on screen but isn't the best design.
U.S.S. Enterprise NCC-1701-A (movies 5-6)
By the end of the TOS film franchise, the bridge went back to looking a bit more like it did on the original series. There are more seated stations along the outer rim of the bridge. There is a large bank of monitors directly behind the captain, however that could be "standing stations". But I think this was really done so that no one would be upstaging William Shatner by acting directly behind him. That's just my theory of course. Part the the design has to be for the sake of production and cinematography, however. With this design Captain Kirk has a big bank of blinking lights and changing displays behind him in most shots. Verdict: B+ This is really one of my favorite designs. I can't find much wrong with it to be honest. Although I have to point out that the Star Trek VI version (pictured here) is much better than the beige Star Trek V version. And somehow the turbolifts move in between those two movies-... somehow.
U.S.S. Enterprise NCC-1701-B
This is basically just the USS Excelsior's bridge with some modifications. Honestly, these modifications are a marked improvement on Sulu's bridge. There is an added station in the back-- which makes the master systems display behind the captain look like usable space and not just decoration. There is also a combined helm/nav station which feels more like TOS than TNG. This bridge was supposed to feel like a transition from one to the other and it pulls that off nicely. Verdict: B Seems appropriate, right?
U.S.S. Enterprise NCC-1701-C
Verdict: D The only reason I'm not giving it an F is that there are worse designs out there.
U.S.S. Enterprise NCC-1701-D (TNG)
Ok. Here we go. With Star Trek The Next Generation Roddenberry really wanted to turn the whole idea of bridge design on it's ear. He wanted to reject anything that was militaristic and asked designers like Andrew Probert (who's work is to the right here) and Herman Zimmerman to make the bridge warm and welcoming. He wanted the Enterprise, the flagship of the federation, to be a ship of peace and it's main bridge should be a work center for collaboration, negotiation and scientific research-- NOT a military command center. So, gone was the idea of the captain's seat being raised and in the center where he can see all the work stations and computer displays. The early designs included a conference table in the middle of the bridge or potted plants and comfy sofa like conversation pit areas. I think this kind of bridge would have been fascinating to see realized, but it was redesigned to look like this. 
Looks familiar, right? Some of the original concepts stayed. The wooden semi-circle is there along with carpet throughout, the bank of science and engineering stations all tucked back out of the way. Even the sofa like seating remains in that the captain's chair now has 2 seats on either side to encourage collaboration. It's not really a hotel lobby anymore, but it still doesn't look like a military command center. It reflected the difference in the TV show when compared to its predecessor. TNG had a much more ensemble cast and the shorelines often revolved around Captain Picard negotiating a treaty-- rather than hopping around the galaxy like a cowboy sleeping with green slave women as Kirk did. 
In my opinion, however, this bridge design was greatly improved in the first TNG feature film, Star Trek Generations. Here they raised the command seats up two steps, gave the tactical officer (Lt. Worf) a seat-- you know how I feel about that-- and added additional stations on the right and left sides of the bridge. Now THIS bridge looks like a place from which you could run a galaxy class starship! I understand why these side stations only appeared in one episode of the tv show ("Yesterday's Enterprise"). If you put stations there you have to have people operating them. And that means paying more extras. With the feature film budget this was no longer an issue. I guess that's why-- I'm not really sure. In any case...Verdict: A+ With the improvements they made on the bridge for the film-- this is my favorite design. To be honest-- it might have something to do with my nostalgia since TNG was my first Star Trek tv show... but I'm sticking with my verdict.
