Have you noticed the title sequence of each show does a pretty good job of describing each show?
TOS: Cheesy graphics and odd music
TNG: A 1980's remake of the original TOS
VOY: Wondering around with no real objective
ENT: Pointless and seemingly random.
Only DS9's sequence seems to be unrelated...
Ahem... yes the TOS graphics weren't good but I recall something like it was underfunded... TNG was good and the music wasnt that bad (compared to some), for Voy I recall the reacuring theme of "lets get back to fed space"... and Enterprise was sorta like "the evalution of the Enterprise" from the HMS Enterpize to the NX-01.