When editing labels and you need to have the degree or diameter symbols I found that this works.
Hold down the <alt> key, type from the numeric pad one of the following (Number lock must be on)
0176 = °
0177 = ±
0216= Ø
0248=ø
as you release the alt key you will receive your symbol. These are the ones i use most often, if you use any others or discover any others, please share them with me. :)