Depends on upstream equipment, even cabling, if your system doesn't produce much bass, HD800's will sound bass shy. If your system produces good bass, HD800's will make good bass.
Overkill actually but that said there certainly isn't a downside to higher bit or sampling rates other than storage assuming your gear CAN actually do higher rates without dropping to a lower operating mode. Ie most DACs before the Sabre days can't do 192 without dropping down to 4x oversampling. Which is why the Benchmark DAC1 chose 110K? as their upsampling number because it's the ceiling for keeping 8x oversampling. That's completely ignoring that it's easier to generate and read a 44K spdif stream than a 192K one.
In my system I find that I can't hear much improvement past 24/96, but 24/96 sounds clearly better than 16/44.1. I think a lot has to do with the upstream digital components, and as you say the maximum sampling rate the DAC can handle without dropping the oversampling filter multiplier. There's no point spending extra money, using more HDD space etc unless improvements can be heard with the equipment one is running. In any case HD800's wont be the bottleneck.
@preproman those are great looking cables, even if there is no difference to hear, one has to admire the work that went into these, the attention to detail EG the modified connector etc. RE dust filter it depends what other damping mods you are running. The drivers themselves have a pretty fine (small holes) mesh screen over them, so I wouldn't be concerned on that front.