I remember when my parents watched the original Terminator when it was first released on video, and I was allegedly too young to watch it. Mum was excitedly telling me all the next morning of the whole factory ending to the movie, and I couldn't help but feel stoked this thing existed/bummed I couldn't watch it. (See also: RoboCop)
I wore out two VHS copies of T2 as a kid. That is one of my all-time favourite flicks, man. There's nothing else to be said about it that everyone doesn't already know.
T3 was not great. Every time I hear Dan enthuse about it, I get a little caught up in his excitement and think, "yeah, that does sound like a kick-fuckin-ass movie!" But then I actually remember the movie and can't go with him on it. But I still always love Dan's unabashed love for that flick.
Terminator Salvation I actually really enjoyed a lot (going in with low expectations helped). It's not the best movie ever made by a long chalk, but it does do some cool stuff and is a pretty decent little potboiler entry in the series.
Never seen the TV show, despite wanting to.
So, I guess in summary for me it goes T2 > T1 > Salvation > T3. With a view to watching and finding a place for the TV series in there somewhere in near future.
If you're ever in doubt about Dan's awesomeness, you should check out his work on the Game Informer Replay & Super Replay video series. Dude's always been my favourite there – the way he gleefully revels in dumb shit was always the best thing about those GI videos – so the fact he's here now has made Giant Bomb content that little bit more of a one stop shop for some of my fave gaming personalities.