I wanted a unique IP when I read about concerns that sharing an IP could harm your site but search engines have done well in recognizing that my site has no malware etc regardless of the other sites on that IP. Until bandwidth and speed become an issue I don't recommend a unique IP address anymore.
I think the local cable company is offering a superbowl deal on cable/phone/internet with DVR on each TV. Just think, 5 TV's + 5 DVR's + Voip phone + 2 computers running on WiFi = how many IP's being used up?
Website owners aren't the biggest abusers.