Depends on features you want. The A7n8X deluxe come with firewire, the Soundstom audio, SATA and dual channel DDR, while the A7n8X-X doesn't come with firewire or SATA, and is a single channel DDR board with a more generic onboard audio.
The dual channel itself isn't really worth the money since game benchmarks suggest it doesn't make much of a difference. Figure a hypothetical DAW benchmark would generate similar results. Dual channel DDR generates higher scores in memory benchmarks though. IMO, either way you go, you're better off spending more money higher quality memory that can handle a 1:1 FSB/DDR ratio beyond 200 Mhz FSB while running CL2 instead of CL2.5. This has more of a real world impact on performance than the dual channel memory capability does.
Of course, if you think you might want Firewire and SATA at some point, you might as well spend the extra $40 and get the Deluxe. For a raw board though, the A7n8x-X is a pretty nice. Has lots of overclocking features which make it a good match with a 2500+ Barton if you plan on overclocking for a little extra bang for the buck.