Direct Mailing List Providers?

Has anyone used any direct mail list providers with any success in your mainstream ventures?

I know direct mailing isnt really used for sites that sell 'product' per say but we're looking at getting some new business clients in the local area and were trying to get some feedback on this method of attracting customers.

From what we can tell right now, based on research we have found on the web and from what some of our friends tell us, the response rate to direct mailing seems to be in the 2-4% range, this is actually a nice level IMHO especially considering that we'll be offering business related services.

So has anyone on GWW used direct mailing before and, if so, how di dyou find the results and where did you find the contact lists from?

Regards,

Lee