Sabato's article for RealClearPolitics summarizes where he believes the races stand exactly two months before the midterm elections on November 2. The article is long, detailed and comprehensive.
Sabato doesn't speak about every last House race, but covers all the governors, all the senators, and deals with the House races in the aggregate. This column is for the real politics wonk, not for those with casual interest. That said, it is a good read, but this year Dems won't enjoy it much.