The Thirteenth ACM SIGKDD International Conference on Knowledge Discovery and Data Mining will take place in San Jose, CA, USA from August 12 through 15, 2007
I can't make it this year. It was going to be my first, but I will be providing training that week. Everything (including its reputation) indicates that it is worth attending for the data mining crowd. Maybe next year. I have joined the SIG (special interest group).
My new plan is a possible attendence at The 18th International Conference on Algorithmic Learning Theory. OK, I admit, the location is part of the appeal. http://www-alg.ist.hokudai.ac.jp/~thomas/ALT07/alt07.jhtml