I assume that the chances for you being sued for your domain are much lower than the chances of Google randomly disabling your account. Which has happened in the past: http://news.ycombinator.com/item?id=354593 and http://news.ycombinator.com/item?id=2798048 - seems that for some of the disabled Google+ account all other Google services have been disabled too. If the registrar steals your domain you would still have the possiblity to go to court to get it back. If Google disables your account you can't do that.
The highest (but still small) risk when having your own domain is that some company claims it has a trademark on the name. But you can mitigate this my (1) using your real name or some other nickname as the domainname and (2) using the .name namespace instead of .com.
The highest (but still small) risk when having your own domain is that some company claims it has a trademark on the name. But you can mitigate this my (1) using your real name or some other nickname as the domainname and (2) using the .name namespace instead of .com.