[FaceOfGkar]

IMO it's a bit much to worry about the movies and other spin off media the first run through. Heck, I and many people I know didn't even catch all of the plot detail in the series itself until the second run through! My suggestion is to just watch seasons 1-5 - it's a pretty obvious order and the story is very well told, the other media is not needed AT ALL in order to watch through. Then I'd suggest watching the movies and reading books etc to expand the storyverse, if you were interested enough in it.

That's just my opinion though. The series is really where the story of B5 is. Everything else is just butter, makes it taste better, but not necessary at all.