Best way to determine how competitive organic keyterm is?

I know I sound noobish here, but the main responses I've heard are:

1. using google keyword tool to see what people are bidding in adwords for term (doesn't tell u how competitive it is organically...)

2. looking at how many results or pages google returns... (again, doesnt tell you how many people are actually link building or actively trying to rank for term)

Please help!

Thanks

hey guys- i know one of you can help me, cmonnn