What's included in an export?

I’m currently working on a model that I plan on putting up for sale on Turbosquid or a similar site. I’d like to make it available for more packages than just Blender so I’m wondering about the export process. It sounds like .obj is relatively universal.

My main question is this: How much information gets exported? Is it just the geometry or are materials, textures, rigs, modifiers (like subsurf) and anything else included?

Question #2: Are there any other formats I should export to? I see there are scripts for a lot of different formats. Do they work well? Is it worth trying to export to the native formats for other programs like Maya or Max? I don’t have any of the other software, so I wouldn’t be able to test it myself.

I’m still using 2.49, by the way.

Thank you for ANY help you can offer.