Anybody starting Babylon 5 must remember to watch the pilot movie The Gathering before starting Season 1.
Always preferred Jeffrey Sinclair to John Sheridan. Great character and a very troubled man. Wish I'd gotten to meet O'Hare at a convention to tell him how much I loved his performance. His narration of the opening titles was much better than Boxleitner's effort the following year.
I've watched all 5 seasons, and I still haven't seen The Gathering (or In the Beginning, or any of the movies). As for the Sheridan/Sinclair debate, I can't pick a side. I liked them both.
As for which show I voted for, I went with B5. Still, SG-1 is a great show with characters I really enjoyed, its just not quite as good as B5. That doesn't make it bad by any means, its a great show with memorable characters and story/