I tried advertising on Google and was disappointed with the results. I
suggest you take advantage of their flexibility to do a couple test runs
before laying out the big bucks. I've been disappointed when it came to
online ads in general. I think advertising in offline medias is at least
as effective. Might try a Google ad along with an ad in say a magazine
that deals with the same things your client sells.

> I personally use Google.  I got a few clients getting ready to lay out
> some serious cash for advertisement.  I'm pretty sure Google and Yahoo
> are the 2 best.  Any reason why not?