Best tools for cpc research

Hey guys I've been doing AM for about two years now on and off. I had a few good site back in the day but it was all black hat and I don't want to do that anymore. I haven't been active for a while because I've been learning how to design website but now I feel like I need to get back into marketing because that's where the real money is and I really want my piece of the pie.

When I first started marketing I never did any research. I just started a site and hoped for the best. Most of my sites failed and I know that's the reason why. I wish I would have listened but I'm hard headed and I needed to learn the hard way. I just read thread on creating sites around high paying adsense ads and I really want to give this a try. What are the best tools out there to get detailed information on the highest paying ads, click through rates, monthly traffic, etc. ? These tools could be free or payed it doesn't really matter but I would like a good free one just to do some quick research right now. I did a quick search and found a site called SpyFu. Has anyone used it or have any info on it? Thanks in advance I really appreciate the help!