Wow some of those on everyone's list make me all warm and fuzzy. As far as mine are concerned:

(in no particular order ofc)

Boondock Saints
World Trade Center
Gladiator
Saving Private Ryan (I also include the mini series Band of Brothers with this.)
3:10 to Yuma (the original, although the new one is very good too.)
Super Troopers (don't ask)
Lord of the Rings Trilogy (Return of the King is by far the best of the three.)
Blood Diamond
Blow
High Fidelity (how can you do an all time favorite list without this one?)

there are a lot of other movies that could be on this list but I think these are the ones I can watch pretty much anytime