Due to the terrain here, I have a 50/34 front (compact cranks) and 11-25 cassette., and a preferred cadence between 90-100 depending on the grade or lack thereof.
I'm sorry, but that's just a recipe for unreliability. Surely mountain bike dérailleur can take up that much slack? (I only ride road bikes, so I don't know)
If not, I believe the new SRAM Apex groupset will be able to support it - it has an 11-32 cassette (http://www.sram.com/node/2121/brand/sram-road/src/cat)
I'm not sure what 27-inches means. I have a 28 tooth back/42 front as my minimum. One day climbing Centiniel drive - to the Lawrence Hall of Science, I noticed an old guy walking was quite able to keep up with me.
There are better methods around, but this is probably the most popular. I imagine it's because the better methods involve harder calculations.
edit: grammar, punctuation.
It's the distance the bike moves in one revolution of the crankset
I prefer to use development as my unit, taking into account the actual circumference of the wheel and tire. Only at that point can you compare apples-to-apples among a broad range of bicycles.
I can understand using a chart to plan things out ahead of time, though to me it seems that it is easy to figure out workable gears when starting out just by riding and eventually you know how to shift in a given situation. The more serious riders will refine that by trying out different combinations in more controlled experiments (power meters when you get to Serious Training). The best gearing always depends on the rider.
I'm not sure how useful it is though. It's not often I'm prepared to do a back & front gearchange at once - I just loose too much speed when I have to easy off the gears.
I suspect that as electronic gear shifting (Dura Ace DI etc) becomes more prevalent the gear system will take care of this for us, though. One click = next gear, no matter how many physical shifts it needs to do.
It's good to hear that there's finally going to be some competition in the high end hub gear space. Even if I don't expect to on the market until my Rohloff breaks down, which might take a while... :-)
EDIT: Looked at the Wikipedia article. Wow, there's no comparison!