Thanks everyone - yeah, sorry I guess I should have said more about what I would be using it for.
I am not a 'gamer' at all so as I've read that is a really big driver on which way to go for some people.
I want to watch movies (I am currently using my iPad to watch and would also want to download and watch on a larger screen).
I hadn't considered the TB Display but thanks for suggesting that - I do 90% of my 'computing' with it sitting on my lap, or on a plane - but for those times when watching a movie stationary, that would be much easier on the eyes!
I really might want to someday edit video - right now just doing simple photo editing - so that makes me thing I should have a system that would give me the ability to do so, but I don't understand the differences in technology yet to know what I need or don't need.
I subscribe to the lighter is better school, although I do think we get carried away in searching for the almighty feather-lite system. Air is currently great, but a slightly heavier refreshed Pro would be fine too.
I do mostly my iTunes and office stuff, and don't know what the future holds for my uses (my crystal ball cracked the other day, so I'm SOL on the predicting front).
I am still using my first gen iTouch and it looks brand new and still works perfectly for me. I'm a buy-and-hold guy, so this one has to be "the one" for the next 5 years or more.
Hope that helps - again, thanks everyone for your input - this is really helping!
good luck!!! BTW, the Macbook Air is not user servicable, which means that you cant replace parts in the laptop later. Therefore, MBP will be more future proof