As an Earthlink customer, I'm actually pretty happy. I've got my DSL through them and some Web space which is accessible through standard FTP. The customer support so far has been quite savvy and Mac-friendly. All in all, a better choice than my last ISP, AT&T WorldNet.
Of course, I'm not a business customer so that may have something to do with it.
I think Apple has a piece of Earthlink and they get a spiff for each new member. (This is from my memory of the MWSF 97 keynote)