TNG was great but it has aged horribly. Some incredibly fond memories there, though.
DS9 is my favorite trek. I'm watching it again right now. Just got to season 4 and am remembering just how

this shyt is. Sisko is the fuccing man, but I think my favorite character is Garak.
Like others have said, SG-1 is another great.
It's a different kind of show but imho it holds up the best. Definitely some weak episodes in there but once they finally kill the first villain (Apophis) the universe really opens up and stakes get raised to much higher levels. It's kind of funny because the show supposedly lasts 10 years. At the beginning of the show, they have technology comparable to what we have today, but by the end of the show, they could give the Federation from Star Trek a run for the money, technologically.
But, alas... Babylon 5 is the greatest of all.