Undisputed 2-3-4, Transporter 1-2, JCVD and SS "classics" if you are into that, or for movies not strictly martial arts focused but with plenty of fighting there is the Bourne series (Matt Damon) / Taken series (Liam Neeson) / John Wick series (Keanu Reeves) and even films like Equalizer, Leon and other more "arthouse" ones.
Best pure martial arts movies IMO still remain the ones with Jackie Chan, Jet Li (the few with no wires) and some others ... all asian productions. Stories are often silly but martial arts action is top notch.