Babylon 5 was one of the best shows ever. B5 is why DS9 started getting good. They saw it was possible to actually tell an ongoing story and people would tune in. You don't have to wrap up everything by the end of the episode and start over again the following week. Even TNG fell into that trap and for the most part it doesn't really matter what order you see the episodes in.
B5 was planned from the start as a 5 year story. S1 hits it's stride about midway and once into S2 you can't wait for the next episode. S5 was kind of tacked on because it wasn't sure there would be S5 until after S4 was done so JMS wrapped up the main story in S4. The movies and the spin-off are good too and I heard rumors that they were trying to do more B5.
The newer Battlestar was a great show, for the first few seasons. Then in my opinion it really just fell apart. The last season just never lived up to the expectations.
As for ST I grew up watching TOS and still love it. I didn't start watching TNG until the second season or so because I hated the thought they were trying to redo one of my favorite shows but once I started I enjoyed it.
DS9 didn't start out all that great but once they figured out they could do an ongoing story and got into the Dominion War it got good.
Had high hopes for Voyager. Voyager sucked. Seriously, I hung in but it never got better. Yes Jerry Ryan was nice to look at but the show sucked.
Enterprise had the worst opening. Seriously, why did they think that song would be a good choice and why did they stick with it? The show itself was great. Started a little slow but any new show usually does. One exception is Firefly, that is one show that hit the street running and never looked back, shame what happened to it. Remember watching the first ep when it aired and was blown away. Back to Enterprise I loved it. I liked Bakula from Quantum Leap and they made it an ongoing story instead of week to week storytelling. Plus Jolene Blalock. To me the hottest Vulcan ever and my favorite Trek girl. Yes I would take her over Jerry Ryan any day.