I have tried almost every connection for a DAC. Of course, it depends on what the DAC will accept, but over the course of at least 100 DACs, this is my take on the best:
1. I2S
2. Firewire
3. AES/EBU
4. Coax with BNC
5. Coax with RCA
6. USB
7. ATT Glass Fiber
8. Toslink
1. I2S
2. Firewire
3. AES/EBU
4. Coax with BNC
5. Coax with RCA
6. USB
7. ATT Glass Fiber
8. Toslink