God, where do you even begin with jazz? Love, love Coltrane's two Village Vanguard sets (despite being drastically different), and the final "Olantunji" concert is still one of the most powerful statements of purpose I've ever heard. Too much to choose from, but Blakey's sets at the Cafe Bohemia and the Coltrane/Monk set that came out last year get very regular play around here.
...and speaking of contrast, the Masayuki Takayanagi/Kaoru Abe duo CD's "Mass Projection" and "Gradually Projection" are such beautiful examples of the amount of variety two improvisers absolutely tuned into each other can bring to the table. "Mass Projection" is a vicious firebomb of a record that, at times, sounds like the hulls of two ships scraping painfully together...a purely visceral, massive sound with jagged shards of guitar and a thick, muscular and distorted sax sound that sounds like it would be impossible to draw from the instrument. It stands in stark relief to "Gradually Projection" recorded the same night (I believe...don't speak enough Japanese to read the liners

) which finds them stripping their interactions down to the skeleton, weaving in and out between each other. It's actually quiet enough that you can actually hear the conversation going on in the restuarant where they're playing, the telephone and the till opening which complements the music almost percussively. Superlatives aside, I can't say enough about these two amazing sets! Their "Kaitaiteki kokan" release is an interesting document of an earlier meeting, but it's on these two sets that they fully metamorphose into a two headed MONSTER!
I don't actually have the discs with me while I'm typing this, so please excuse any errors. But anybody who has any interest in Free Jazz live sets owes it to themselves to check these two out.