I've been trying to find a reasonable guide to setting up a bike to fit your size on the web, to no avail... having watched a couple of high-level bike mechanics fit bikes to people I think their is an art as well as science to it, and even what you are using the bike for is highly relevant.
Anyways, I did find this some time back and found it an informative read on generally what you want, ergonomically...http://www.junik-hpv.de/assets/download ... People.pdf
that being said...
I am fairly tall (185cm) with long legs. I find when I am relying on my legs and human power as part of the electric bike mix, that I prefer to have my leg Almost fully extended, from arse to pedal (not extended to lockout of the knee, maybe 5 degrees off) so I can get consistant grinding power out of my legs, and I'll just pop of the saddle and ride the pedals if I really want to power, or if I want to use my legs as shock absorbers going over bumpy ground.
This basically means that seated and stationary, I can touch the ground on one side on tip toe.
I find this seat height no problem for light MTB type stuff as well, BUT if you are going to be doing fairly hard core Mountain biking, you probably want the seat a bit lower, not so much for pedal power but control so you can get your weight more over the back wheel, if going downhill or jumping n such.
Personally, I tried to set a bike up so that I am lightly grasping the handlebars, in a standard riding position, without having to lean down on my arms or pull back on the bars to be comfortable.
If I am going road-oriented, I want the bars lower so I can reduce my wind profile, if I am going off-road I prefer the bars higher so I can throw the bike around more...
But anyways, I think... pedal power, .. look to how extended your legs are and adjust for that, for comfort/ergonomics, ensure weight is more on arse than wrists. this may mean adjusting headset.
Hope that helps