I suspect that you're hitting your real RAM ceiling and your machine is swapping when you're loading or connecting to games. I'm guessing you're at 4gb - I sincerely hope it's not less.
To confirm, open up Activity Monitor (Applications > Utilities) and go though all the steps of loading and connecting to a game. Switch to Activity Monitor while you're in a game, your System Memory will probably have very little "Free" memory left.
You can attempt to free up more RAM by quitting other applications that are running when you're playing TF2, but I suggest upgrading to 8gb (if your machine supports it). It's under $100 and makes a huge difference when doing all sorts of RAM-hungry stuff (photoshop and parallels at the same time? not a problem!).
Or, you can try to adjust the settings down to a more manageable level for your amount of RAM. Lowering the texture quality is probably the easiest way to achieve this, but try out the rest of the settings to see what works for you.
Note: This answer's numbers have been updated with numbers from the client sizes. The server size is much smaller.
10.5GB is correct. Of this, 3.68GB are shared files from Half-Life 2 and Orange Box games. That leaves 6.82GB specific to TF2. This is a logical progression from the 4.85GB TF2 was at when update 119 was pushed a year ago.
Team Fortress 2 is split up into 6 distinct packages on the Dedicated Server side, totaling 5.8GB.
TF2 is split up into 11 packages on the client side, totaling 10.5GB.
The client packages are:
- team fortress 2 content.gcf - 3.95GB
- team fortress 2 materials.gcf - 2.84GB
- team fortress 2 client content.gcf - 27.5MB
- source 2007 shared materials.gcf - 985MB
- source 2007 shared models.gcf - 148MB
- source 2007 shared sounds.gcf - 2.26MB
- source materials.gcf - 1.02GB
- source models.gcf - 449MB
- source sounds.gcf - 975MB
- orangebox media.gcf - 7.55MB
- multiplayer ob binaries.gcf - 155MB
I can break down the TF2 Content package further. The only 5 directories larger than 25MB are:
- bin/ - 40.1 MB
- maps/ - 2,364.5 MB
- media/ - 620.7 MB - Movies that play the first time you play a map
- models/ - 426 MB
- sound/ - 901.1 MB
The problem is that most things in Source games are uncompressed. All non-music sound files are 44Khz, 16-bit mono wav files. There are also 11 compressed music files that are 128kbps 44Khz 16-bit Joint Stereo mp3 files.
Map files are stored uncompressed, despite Source understanding the Bzip2 compression algorithm. Valve ships 51 maps files: 48 are multiplayer maps, 2 are Training maps, and 1 is the Item Test map.
The average map size is 47.6MB... unless you take out the training and item test maps, then the average size is 49MB. Arena maps are typically smaller in size, while multi-stage maps (like Dustbowl, Goldrush, etc...) are typically larger.
Every new hat in the game adds a number of files. It adds 4 models, possibly 1 physics file, 2-4 material files, and 1 backpack icon file. As far as I can tell, these files are all fairly small... they add up to around 2MB for the Portal 2 Pin.
Best Answer
The point of the game is to work together as a team to defeat the enemy team. There are now two primary modes:
Keep in mind TF2 is a "class based" shooter, which has nine roles, which each play very differently.
Your choice of starting class will likely depend on your experience in other games. Soldier, Heavy, and Sniper will probably be the most familiar to players of FPS. If you haven't played a lot of FPS I'd suggest Pyro, since it's a little less particular about aim, and doesn't require the strategy of Medic or Engineer. The game does feature training which I would suggest using before jumping in, it'll get you familiar with the classes and controls. After that find a multiplayer game and jump in.
You may also want to check out the Official TF2 Wiki.