Team Fortress 2 has been in development for the better part of ten years and thankfully doesn't disappoint.
In addition to the weapons mentioned previously Valve has started releasing new class packs which contain 36 achievements and 3 unlockable weapons. Examples of these new weapons are the Medic's Ubersaw which increases their ubercharge meter with every hit, and the Pyro's flare gun which can be used to ignite enemies from afar. Selecting one weapon will require you to swap it out with another. For example the flare gun replaces the shotgun with the Pyro.
The graphics are beautifully cel shaded which gives the characters a great amount of character and personality. Each class is from a different part of the world, the Scout is from New York, and the Demoman is from Scotland and their accents show this. Speaking of which all of the voice acting in the game is well done and provides much variation with certain voice commands. The music is also well done even though you don't hear much of it except for when starting up the game and listening to various winning or losing themes.
There are several types of gameplay variants. Control Point (available on maps with cp_ in the name) can be that there are five control points and the two teams are in a tag of war esque struggle for dominance, or there are two points, red defends them, blue tries to capture them. If red wins game over. If blu wins three times in a row then they win. In Payload (pl_) players on blu stand by a cart with a bomb on it and that causes it to move forward. Red tries to prevent blu from accomplishing this. Then of course there's Capture the Flag. (ctf_) Of course you take the enemy intelligence and take it back to your base. This mode was altered slightly from the last game as there is no flag but an intelligence briefcase that emits a shower of papers to show the trail of the one who stole it. There is always room for additional game modes as shown when Valve introduced Goldrush which became the first payload map.
As far as map variety goes it's endless. There are several maps that come with it and then there are many user created maps. Starting with the Pyro update Valve started taking user maps and throwing them into official rotation. Maps can be anything. There was one called MARIO_KART which was just a team deathmatch style game on a bizarre map that features many many themes such as Haruhi Suzmiya and No More Heroes. That's right I made a Haruhi reference in a FPS review.
All in all this is a quality game with excellent support from the developers. Unfortunately console gamers cannot experience the full quality of the game as Valve and EA has yet to release the new content on the 360 or the PS3. This is mostly because of Sony and Microsoft's guidelines. On Microsoft's part you can't continually add achievements till the end of time like you can on Valve's Steam service. And of course the PS3 doesn't have support for achievements although the trophy system probably won't see updates for The Orange Box due to the fact that it's published by EA and they're not known for going out of their way to help out gamers and add new content when they really don't have to and that's a shame. This is a addictive competitive game that will be played and supported for many years to come.