Large format photography, be it 4x5, 8x10, or 20x24 is not simply about "making photographs", but an entirely new discipline. With large format photography everything changes. The subject matter available to you, the way you plan your shoots, and the methods and sequence involved in actually taking each individual photograph. Each of these aspects involve an entire array of considerations. It's important that you understand how all this relates to your particular preferences and creative style before making what is sure to be a sizeable investment.
I wholesomely concur with my colleages on Apug who have suggested you start with 4x5. First off, it's a far more versatile format then any other, and one that would truly offer you a glimpse into the world of large format photography while still offering you a choice from practically any of the available output methods (printing). With 4x5 you would quickly learn all that's involved in shooting large format, yet still be able to choose between enlargements or contact printing, and sample from the (relative abundance of) 4x5 films available, a far wider selection compared to the more limited variety of 8x10 and larger sizes.
In shooting 4x5 you would quickly learn the many pitfalls associated with 'over-gearing', and find your own personal 'middle-ground'. Even if you choose to move on to a larger format, your experience with 4x5 would only serve to guide you in selecting an appropriate camera, lens and accessories, finding that which is best for you, and not having to rely on the numerous, and often conflicting preferences of other large format photographers.
As for equipment - I would go along with the suggestion of purchasing a well-preserved Crown/Speed Graphic "press camera". These are often sold with lenses and are routinely available both on eBay and from local resellers. Start off with about 6-10 film holders, a box of film, paper, and you're basically done. This method is relatively inexpensive, effective, and offers the opportunity to sample the world of large format photography from a minimalist perspective.
Best of luck!