Depends on what kind or racing you are talking about. I ride some MX and lots of trails (for play; not competition) and am about to install a full set of Maxxis Razr's. I've run them before. Good tire, not uber expensive, and performs well in the woods and on the track. Some people would probably call them a good 'all around' ATV tire. You can get a full set brand new from RockyMountainATV.com, with free shipping, for under $ 300.00.
ITP Holeshots are also a good choice; I've run these before, too, and like them.