Normal or Hentai games? It changes over time, since some devs aren't as good as they used to be.
For normal games, Sega and Falcom had always been my mainstay. For hentai, currently HAMHAM-SOFT and Atelier Kaguya HonkyTonk Pumpkin. Go check 'em out.
Dieselmine used to be my all-time favorite...