Is the Integrated Sound on the ASUS A7N8X Deluxe?

yes , onboard sound is great , comparable to Audigy - Audigy 2 series sound cards in my opinion , yes barton will work fine

Not all nforce2 have excellent sound. MCP only which uses the realtek ALC650(AC97)DAC - it's software based. Only the MCP-T boards have digital encoding (does not decode) on the fly. For instance, The Biostar M7NCDP, Shuttle AN35N, regulat A7N8X (non deluxe), Abit NF7 (not -S), A-Open AK79D-400VN,XFX NF24ALH, Chaintech 7NJL4..etc..all are MCP southbridge AC97 only boards. So sound is analog only and ALC650, which is mediocre at best.

There are a few boards with are MCP that utilize the C-Media 9739 codec like the Epox 8RDA3+. But only the MCP-T boards have full digital sound that would be compared to an Audigy 1...not the Audigy 2. AC97 (ALC650) is actually very common, and its really cot even comparable to C-Media 8738 at all. C-media 8738 sounds alot better, and does EAX. 8738 was common in many KT266a and KT333 motherboards of the past, and you can still find them on Soyo motherboards, and a few Deluxe chaintech boards.