I plan on buying Jean-Luc Godard's Vivre sa vie ('62) on Blu-ray when it comes out on 4.20 (reviewed here by DVDBeaver), if for no other reason than I've never seen it and any new high-def Godard is certainly worth spending for.
If I had to go through the French New Wave director's filmography, the cream of the crop would be Breathless, Contempt, Alphaville and Band of Outsiders (all great to masterful). I honestly couldn't make myself sit through Weekend all the way through and Made in U.S.A. is just too Looney Tunes and too self-referential.
I would certainly recommend to someone who hasn't gone through the Godard treatment to start at the beginning with Breathless and work your way up. Anyone who jumps in with Alphaville or Weekend or 2 Or 3 Things I Know About Her will just throw in the towel thirty minutes in.