I would ask first and foremost if you need 8 preamps? I've been down the same road and I've concluded that unless I'm cutting drums (and it would take so much more than an 8 channel interface to get good drums) why bother with that many channels?
I've gone the apollo twin duo route. The fidelity is awesome, and it gets you into the world of UAD which is where some of the best stuff is happening with plugins. It'll definitely help you get better tools to do the job.
If you ever needed more channels you can expand the apollo with the optical input and still keep it as the brain of your operation. But in my experience, I'm usually using programmed drums, or cutting drums somewhere I can get them done right. The apollo twin is perfect for overdubs afterward.