Well, I've always been a huge Pat Metheny fan.....he still rules in my opinion.   I didn't know he had some things out with Brad Mehldau.

As far as Jeff Ballard goes, he blew me away the first time I heard him.  He was playing with Chick Corea then (about 4-5 years ago) with Avi Cohen on bass.   It was clear to me, he was one of the most amazing jazz drummers of all time, especially with that very amazing polyrhythmic stuff he does.  I've noticed that he is certainly emerging as one of the pre-eminent players in recent years.  I met him backstage at the Chick show, and he was such a nice, sweet guy....really very humble.  

Since I know you love piano, check out this guy who plays with Dave Binney these days...Craig Taborn.  He is from another planet, 'cause nobody can play like that....is it even possible?  

Binney's site is pretty decent, and he has downloads including sections of whole gigs...

http://www.davebinney.com  or something like that.

Gene