I think you might actually might want to mix on a few different loudspeakers and headphones to get a feel for it.
The HD800 is great for looking deep into a recording and finding hisses, crack and other nasty things.
A regular set of loudspeakers like B&W 801/802 powered by something like a NAD amp is great if you can afford it, this is where you want to fine tune your sound and find the correct levels. Can also be a smaller set of nearfield speakers.
A cheap set of sony or sennheiser in-ears is great since that's how a lot of people will listen to music.
If you find something that sounds great on all three of these you're probably on to something.