You might also be interested in learning about a series that Peter Thompson at "The Guardian" is doing on Karl Marx. I haven't worked through it all yet, and there may be more installments coming (in which case, I'll try to update this post), but it's certainly all very interesting. Here are links to the different parts, with titles so you have an idea of what you're getting into:
- Religion, the wrong answer to the right question
- How Marxism came to dominate socialist thinking
- Men make their own history
- 'Workers of the world, unite!'
- The problem of power