Keyword Research Advice Please

I'm doing a little keyword research on what's worth my time and what isn't. I'm currently using the following assumptions and was wondering how accurate they were:

- On reaching #1 you can expect 50% of the traffic for that keyword
- From that traffic you can expect a 1% CTR (Adsense) if well placed

So for a keyword with 3000 exact searches @ $1 CPC you can expect to earn around $15 per month. Does this seem about right?

I'd assume a 25% CTR. If it has good advertisers, it will also show adwords ads before organic listings.
After that, YMMY. I generally take 2-3% CTR if using adsense.

Don't just stick with adsense, use other monetization methods as well.