Where can I find a list or database of generic keywords that are used for search and PPC?

For research, we need an updated list of keywords used by people for search and for online marketing (and pay-per-click). I'm sure this list is big, so it's probably a database; and if possible, it should also include additional information, like ranking or popularity. Thanks!

check out Google Adwords keyword tool. You can put in any keyword or URL and get a list of good keywords to add to your PPC campaign.