Your average theologian is a guy who spent way too many years at school and is now searching for a job that doesn't involve fast food.
I'm not entirely joking about this. I've been there and got the t-shirt (Hope College, Western Theological Seminary).
Your average theologian has a bachelors degree in something (classics, religion, or maybe some wacky unrelated field), a masters (in theology or maybe an M. Div), and doctorate (during which he/she staked out some interesting pieces of intellectual real estate and wrote a long dissertation).
By the time you've done this kind of thing you've definitely learned to think hard and logically about theological problems. If you've attended a seminary rather than a divinity school, you may also have developed the public speaking and counseling skills you need to be a pastor.
Not everybody can become a pastor,however. I know at least one theologian, a very bright guy, who was (last I heard) working in a factory and occaisionally teaching as an adjunct professor at a local college.
Nevertheless, theology is cool. See further John Calvin, Martin Luther, Anselm, Thomas Aquinas, Augustine and many others (if you're into the classic theologians). You can also check out more modern ideas like Neo-Conservatives (Karl Barth), more left leaning people like Paul Tillich, the Libertation Theology movement, or the various gender oreinted, ethnic or cultural theologies that have since developed (examples: feminist, gay, lesbian, male-oriented (via the men's movement), African-American, Native American, or whatever). | 
