Okay, may as well give my two cents:
- Essential, though I prefer the revised version they did when B5 went over to TNT. Mostly because of the music. The music of the original was very annoying. In itself, also a good little movie.
In the Beginning
- Nice, but it's not really that important. Has the fantastic Reiner Schöne, though.
- Nice, self-contained movie.
River of Souls
- Better than most people say, it's a nice little movie. With Martin Sheen, though admittedly not at his best.
A Call to Arms
- Essential for CRUSADE. The music is weird, and the technique of having the commanding officers shouting with the sound off during the battles is not used as well as it was on B5 (maybe because B5 did it only rarely). Tony Todd was great.
Legend of the Rangers
- Again, better than its reputation. I would very much have liked to see what the series would have been like.
- The low budget shows, a fact JMS even made fun of in the bonus material (sock puppets). The CGI, unsurprisingly, is very good. The stories themselves are what they are: short stories. Although, you never know, had JMS had gotten the green light for several further volumes, he may have picked up some of the pieces.
Anyway, I never leave out any of the movies (or CRUSADE) when I do my occasional run of B5, but I rarely watch them independently.