rkane Welcome to Flyertalk!
WingnutVonage can do most, but not all of your list. They can do a fax line, but not fax to email. They do a "simulring" on up to 6 numbers when you get an incoming call - a sort of diversion+ You can also have a std diversion. Vonage can email out our voicemail - great for keeping copies, or for spotting new voicemail messages if you are plugged into an iPhone or BB.
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Faxes - so 20th Century. I'd do what rkane says, and go for a dedicated provider - unless you want to hook up a fax to email machine at home.