I have been waiting for the DVDs to become really really cheap, like $10 a season cheap and it just hasn't happened yet. However the first 26 episodes of B5 are on thewb.com so I started watching.
I'm really enjoying it. The last episode I watched was "Mind War" and I'm so glad Sinclair hit the telepath bastard.
My sister used to be a big fan of the show, so I have seen parts of it when it was first on TV. So I know some minor things like Sinclair isn't in command in the later season. If you go to Za'hadum you will die (No clue what that means), that seasons 2-4 deal with the Shadows War, B4 disappeared in time, and that the last season is almost a spinoff in a way because everything closed up in the end of season 4. Season 5 is what I remember most, which is funny because I know it's the weakest season.
I also know there is somewhat a curse of the actors of the show dying rather young, like the doctor and Sinclair and a few others.
But this is my first time watching the show in somewhat of an order. So far I'm enjoying it and can sense there are little things being built up to for the later seasons.