is "OM" by John Coltrane the most mindblowing jazz album ever?
 

... or are there other ones I should hear?

That's a pretty great one. I'm sure you already have, but if you haven't already, check out Coltrane's Ascension and Meditations as well if you like Om. You might like Peter Brötzmann, he's like Albert Ayler and Pharoah Sanders on meth. His album Machine Gun is one of my overall favourites.

Yeah I like Brötzmann. I saw him live once. Blew my head off.

Dude, you're a lucky bastard. I saw Bennink a couple of weeks ago, so I guess that's good too.

Have you heard Don Cherry's album Organic Music Society? That one mixes free jazz and world elements quite a bit like Om (and it's a great album to boot).

No I haven't! Thanks for reminding me. Don Cherry is one of those guys I always forget I'm supposed to check out.

Yeah I saw Brötzmann doing a solo gig, but it sounded like it was a full band concert... :)