Am still enthusiastically watching Babylon 5 and am now up to season 4, episode 11.
My husband has also been infected by the Babylon 5 virus and has watched (nearly) all episodes with me since the middle of season 3. He's usually not the type of person to be overly sympathetic to characters who make major mistakes - he insists on calling Anakin "Little Darth" :-) - so it's a major credit to the show that not once has he said anything bad about Londo. In fact, I get the feeling that he really likes this character, although his favorite is Delenn.
For me the highlights of the show are any scenes with Londo, G'Kar and Vir. I specifically love the interaction between Londo & G'Kar and Londo & Vir. Their scenes are absolutely outstanding!
I'm convinced that Londo strongly identifies with Vir: He seems to see in him an uncorrupted version of himself and as such wants to protect his innocence.
Vir slowly growing up is fascinating to observe. E.g. when Londo calls him his friend, you can see that this does wonder to his self-esteem. This is one of few scenes where Vir suddenly stands up straight - and you realise that he's actually taller than Londo.
G'Kar gets a lot of Jesus imagery in his story arch: Cartagia (apparently modelled on the Roman emperors Nero and Caligula) washes his hands, there are the 40 lashes and a scene where G'Kar is ridiculed. And of course his chains are strongly reminiscent of the cross.
Anna Sheridan: I'm happy to see that she did appear again on the show. I have to admit though that I was a bit disappointed by how this plot point was resolved. I just would have found it way more fascinating if the Shadows had had better reasons for their actions (genocide for evolutionary purposes doesn't cut it for me at all) and that Anna had joined them of her own free will.
Mr Morden: By the end, I felt sorry for him. It seems that the Shadows brainwashed a few selected humans. Since it's mentioned that Anna resisted their influence strongly at first, it seems that the Shadows picked the most strong-minded and ethical people to be their brainwashed spokespersons. So it's entirely possible that Morden used to be a decent human being once that simply became a vessel for the Shadows. So I was sorry for what the Shadows did to him.
Sheridan coming back from the dead: Hmmmmm. On the one hand, I'm glad to have him back. On the other hand, I felt that the price he paid is a bit on the cheap side. Yes, apparently he has only 20 more years to live, but then knowing that you do have 20 years ahead of you is a big gift.
Overall, I thought the introduction of Lorien a bit too much of a deus-ex-machina plot resolution.
What does get my interest, however, is the question: When Sheridan traveled 17 years to the future, did he see a future where he went to Z'ha'dum or a future where he didn't go?
Right now, it seems as if Sheridan is set analog to the Messiah - at least by his followers - whereas Garibaldi gets to play the part of Judas. Not that Garibaldi really is himself at this point. There are strong hints that he was brainwashed by the Psycorps and that Bester knows about it all or is even behind it.
Sinclair and Valen: Brilliant idea! I had strong suspicions as soon as Sinclair received a 900 year letters addressed to himself and I love turning out right. :-))
Delenn: The scenes during the Dreaming are very intense and her pain and rage after Dukhat's death are very powerfully portrayed. Having her responsible for the Earth-Minbari war actually gives her stronger parallels to Londo. They both have a lot of blood on their hands. The big difference is, of course, that Londo chose his actions in cold blood - well, until the death of Adira. Still it's fascinating that in the world of Babylon 5, the lines between black and white are never clearly drawn.