Should I get dedicated/multiple IP addresses?

[Self Made]

I have a typical virtual hosting plan on HostGator. I'm wondering if there's any advantage to me getting a dedicated or multiple IP addresses. I remember a recent post, from Randy Ray I think, indicating that there's no SEO advantage as long as the traceroute is the same. I also recall Google buying a domain name registrar a few years back which some speculated was to get at private registration information (and all my domains have identical info for the most part). So I'm skeptical that there's any SEO advantage, though I don't claim to be an expert. I gather perceived SEO value could raise the value of links if I decided to sell them however.

Another consideration I can think of is someone sending spam from the same IP address making my emails less deliverable. I assum HostGator is good at getting rid of spamers, but should that be a concern?

I guess I don't understand why people buy multiple IPs (and the different c-block stuff I hear about). Is there any real benefit?