In IRC, identd, and Privacy I complained that proxies with SOCKS support were rather thin on the ground - meanwhile, things have improved significantly. Because X-Chat Aqua is now in a state that can be described as very usable - after many years of using Snak, I have actually switched.
X-Chat Aqua supports SOCKS and thus allows direct use of tor. However, this is not SOCKS4A - therefore, DNS resolutions are still visible. Ideally, you simply enter the server's IP address, so no name resolution needs to occur.
With Jabber, things now look very good with PSI - PSI is very usable under OS X and the display problems of older versions have also been fixed. And PSI also works with tor.
Browsing over tor was already possible before, but with the current Mac OS X Builds of tor, it is also very easy to install. Tip: I created my own network configuration, with which I can easily change the proxy settings. With this, I can then simply turn Privoxy+Tor on and off in the Apple menu as needed. Of course, this only works with browsers that get their proxy settings from the system settings.
Using ssh over tor is easily done with the ProxyCommand stuff. Instructions are in the Torify HowTo. Many of the tips mentioned there also work under OS X, as there is a normal Unix underneath.