I'm currently six episodes into series five of
Star Trek: Deep Space Nine.
Definitely a show which improves as it goes along. Helped greatly by the fact the Klingons are now used in the correct way - ie - the enemy.
Some terrific episodes so far with one or two clunkers along the way (usually involving Sisko's son, Jake) The event episodes have all been excellent with the lesser stories the best ones usually feature the likes of Odo, Quark or Andrew Robinson's Garak.
The last episode i watched was entitled
Trials and Tribble-ations and was a joyous celebration of the original Star Trek series in which several of the DS9 regulars end up on the original Enterprise as the ship is overrun by Tribbles.