What series should I read next?

Depends entirely on what you are seeking. Do you want romance or urban fantasy. Do you prefer shifters, demons or vampires. Have you read any sample chapters to see which would you prefer to start with. I am partial to the BDB, but that is because I prefer romance, and the first 4 books I enjoyed the best, as well as Lover Avenged. The series is more romance though it has strong urban fantasy elements, and it does need to be read in order once you are past book 4. All are extremely popular, so I would even dare suggest pick one randomly, and start from there.