Hello, Elaine; it's always good to meet someone nibbling at the B7 bait.
But for some reason it's very hard to recommend specific episodes; I don't know what will appeal to you. One of my favorites of the video set is Volume 25; it has two strong episodes, "Gold" and "Orbit". But those episodes come near the very end of the series, and I don't think you could get the full impact of "Orbit" without knowing all of what had come before.
Perhaps a better one to start with would be "Project Avalon", because it includes all of the original cast; you'd get to see Blake in action. That's on Volume 5; it's paired with "Breakdown" which is only so-so in spite of a couple of strong scenes.
One of my favorites is "Mission to Destiny", which is a murder mystery aboard a spacecraft with Avon playing detective. Unfortunately, its partner on Volume 4 is "Duel", not one of the show's better efforts. In fact, it's pretty bad.
And then there's "Gambit"...and "Star One"...