Quiet interesting tips to be taken care while on Keyword research.

Strength of competition is going to be important, because if you can't crack them you're not going to get any traffic (or very little), so monthly searches and cpc would be irrelevant in that case.

Otherwise assuming strength of competition is roughly equal, I'd go for the best average cpc (monthly searches divided by cpc) so you can work out what you will get per adsense click (adsense pays about a third of the cpc from memory).

Remember though that the cpc figures you will see are worse case, so in reality your income will be based on a lower figure (advertisers optimized ads, etc).

Sometimes the lowest competition will bring you the best revenue if the cpc is not dramatically different from the other keywords if you can dominate page one for that keyword and soak up the majority of clicks.

Hope this helps.

Cheers