I think I must have stopped watching it sometime early in Season 6, because I found that it had become too boring, cliched, repetitive, and ridicilous. I remember having enjoyed Seasons 1 & 2 though, after that fatigue had started to set in.
I actually haven't seen it since then (2008), but I can certainly imagine that it hasn't aged very well, because it was a show that had oozed "Bush era" and "War on Terror" even back then.
The show is much better to watch if you are binging it then watching in a traditional episode per week format .
My parents and I when we watched it the first time around back on Netflix we would watch each season(outside the first) in 4-7 days