My experience matches BRH's. Many of mine are the excellent "American Classics" series, especially of more recent composers such as Charles Wuorinen, Elliott Carter (esp. the Pacifica Quartet's superb version of his quartets), Joseph Schwantner (his superb Percussion Concerto), Philip Glass, John Adams, Richard Danielpour, Michael Daugherty (esp. Fire and Blood), Paul Moravec (Cool Fire and especially Tempest Fantasy), Thomas Leshnoff, Jennifer Higdon, Bruce Wolosoff; also much of the Samuel Barber series. Many of these are not cutting-edge, but they are well-crafted, thoughtful, even exurberant works by contemporary composers.
I also have a batch of Petrenko's Shostakovich symphony cycle, which includes a number of very fine performances (esp. #4, #7, #8, and #10). The Naxos series of Martinu's string quartets and the piano quintets is excellent (by, aptly enough, the Martinu Quartet). And I recently picked up a pair of performances of Takemitsu's works, a superb version of the Chamber Music (And then I knew 'twas wind, Toward the Sea, Rain Tree) and the Piano Music.
What I most admire in Naxos is their "record everything" philosophy. The sound quality has improved immensely in the last decade or so. I still go elsewhere most of the time, but I always keep an eye out for their releases of new composers and new compositions. I admire their risk-taking and will continue to purchase some of their risky ventures. Because of the price, I am more willing to take risks.