Honestly, I've yet to be disappointed with any of the on-board solutions I've used. Most anolog 5.1 solutions sound really good with the proper speakers/receiver... and right now I'm really enjoying my mobo's onboard feeding into my JVC RX-5030V reciever. Sounds great with DPLII.
Not entirely cinematic... but close enough in most cases. I see no need for EAX anymore. And yes, I've used and heard the X-Fi (I own one but see no need in using it).