I've only seen seasons 1 - 5. I own 4 and 5 in the boxed DVD sets, and plan to buy the rest soon. The big battle at the end of season 5 was kinda disappointing, since it looked just like the battle at the start of season 3, only with cardassian and dominion ships, not klingon ones.
One funny thing is the free program you get, which is a big database full of episode listings, race lists, character lists etc, all with episode cross - references. It's kinda juicy.
One of my favourite parts of the entire show is the relationships that Bashir has with O'Brien and Garrack. The lunch talks of Garrack and Bashir are just brilliant, and the way the friendship of O'Brien and Bashir developed was so well done. Garrack in particular is a juicy prospect, since he seems to be turning somewhat... good. Shocking, i know. Please, don't ruin anything for me here. I'm desperate to see how he develops further.
Plus, Garrack speaks almost like a Brit, i think.