A&A http://aaisp.net/

Not cheap, but I highly recommend them to anyone with a technical bent. They are the fairest ISP I know, with no hidden or shrouded limits or costs. Everything is spelled out in black and white up front.

They also have the most detailed and pro-active line monitoring ever, take a look at the status pages for my line:

http://www.norman.cx/photos/links/aa/main.cgi.htm
http://www.norman.cx/photos/links/aa/usage.cgi.htm