Javit

Your best bet for a gueuze/lambic that is true to style would be Lindeman's Cuvee Renee. Their fruit lambics are all sugary messes. Past that you should look into Girardin (black label), Drie Fonteinen, and Cantillon. For Flanders Reds, I would definitely look up Monk's Cafe Red. And don't underestimate the funky tartness of some of the Fantome saisons

fickenmeimirish

Not as high up there as the Drie Fonteinen or Cantillon but still a good one.

kbuzz

If you can get them, The Bruery makes some good sours as well. I've had Mother Funker and Oude Tart - both very tasty sours. But yeah, going back to a previous post, I try to get Jolly Pumpkin whenever I can.

Marco

http://www.ratebeer.com/beer/struise-aardmonnik--earthmonk/58704/

bigkahunabrew

Cuvee Rene' is a really good beer! Lindeman's has one of my favorite overall lines of sour beer... even if most are fruit varieties.
I did a series of Kriek (Sour Cherry Brews) on my blog... Links:
http://www.bigkahunabrew.com/2012/05/kriek-tuesday-1.html
http://www.bigkahunabrew.com/2012/05/kriek-2.html
http://www.bigkahunabrew.com/2012/05/kriek-tuesday-3.html
http://www.bigkahunabrew.com/2012/06/kriek-tuesday-4.html
http://www.bigkahunabrew.com/2012/06/kriek-tuesday-5.html (This is the Lindeman's )

ayoungrad

Old thread, but...

Three different types of great sour beers that are fairly well distributed:

Most Geuze from Drie Fonteinen
Duchesse De Bourgogne
De Dolle Extra Export Stout