So I like when I can setup security (of varying levels), but do it in a way that's so transparent, I get all the benefits of the security, without any repetitive tasks. Lately I've been wondering about keeping my general net activities private, at least within the scope of my local network connection, when away from home. In other words, if I'm sitting at a coffee shop, using their wireless connection, my laptop should know, at least, that I'm not home, and automatically turn on various levels of security between my laptop and the outside world. Most of my various network activities already handle a lot of encryption, but there are various holes in that here and there. It also doesn't do anything to obfuscate where in general my network traffic is being sent. I believe it should now.
After getting SSH Keychain setup, add a new tunnel to it, under preferences. Have it launch when keys are added, and after sleep / on startup. You should also probably have it use compression. No local or remote ports. Under Dynamic port forwards, setup something, like 9999 (used for the rest of these examples).
You will need at least 2 locations for a setup like this. One will be your home location with no proxy setup. The other will be a "secure," or roaming, location. This location should have a SOCKS5 proxy setup as 'localhost' port 9999.
The above takes care of a lot of OS X apps, but Firefox for example, has its own proxy settings. I just happened to find System Proxy which automatically syncs your OS X system proxy settings to Firefox, complete with location switching support. In other words, it just works, and keeps Firefox synced properly all the time. (Also works / with Thunderbird). It simply puts a check box (sync with system settings) in the Proxy settings pane Firefox already has. That's all it does, and all it needs to do.
Marco Polo is pretty awesome. Based on a lot of environment options (external monitors attached, bluetooth devices, wireless networks, ethernet networks, etc) it can subsequently pick a preconfigured Marco Polo "context." Finally, numerous actions can be performed on context switches. One of those actions is to change the active OS X network location.
So in summary, Marco Polo determines where you are and what OS X network location to use. The network location determines which proxy, if any, to use. System Proxy keeps the proxy data in sync with Firefox. I, pretty seamlessly from here on, have automated privacy when out and about.
I checked and all the Adium account settings have proxy support. The best option is "Systemwide SOCKS5 Settings." This once again, without any work, just does the right thing when I'm out and about.