To me the top sci-fi shows in my lifetime is Babylon 5, Firefly, and the new Battlestar Galatica..
I absolutely love Babylon 5.
In every society I ever heard of there is a tension between the center and the regional. Such a tension did not exist in Star Trek. In Babylon 5 we had an outright civil war between the outer colonies and President Clark's "Empire of Earth" policies.
Noone remembers Space: Above and Beyond. Much better than the soap opera in space B5.
Of course, they had their share of drama, but the acting and camraderie was much better, and Morgan & Wong did just a great job of writing.