If there are 80 million people working 10 million officially unemployed, and 10 million discouraged workers, how much is our unemployment rate?

Depends on who you ask. Whether discouraged workers are "unemployed" (as opposed to "not looking for whatever reason") is a matter of opinion. So seriously, depends on who you ask.

My opinion is they should be considered unemployed cause they were intending to get work and perhaps should be working. (I suspect some of them are people who don't need to work, but most probably do.) When things are as bad as they are now, that's a significant number and I don't think can be ignored. If nothing else, at least give a percentage of discouraged workers, even if they aren't included in the unemployed bracket.