I have never seen Thirteen Days (and don't intend to), but the other three all very good films in my opinion. A very diverse selection at that
For
Léon, I'd say make sure to get the (longer) International Cut. The shorter US theatrical release had several key scenes removed.
Apocalypse Now is a classic. The story behind the making infamous. It's not a war film though, which could be "enjoyed" for it's action while having a few beers. You might know this, but I thought I mention it anyway.
The Vengeance Trilogy are all independent films, connected by theme, not story. I like the other two also, but
Oldboy is the best.