I have read various things on the subject, but I'm still not convinced either way. Any opinions on the subject?
There are potential advantages to having a dedicated IP address. 1. A dedicated IP is required if you want to use a secure certificate. 2. I have seen sites banned from corporate networks because they share an IP with another site that the company filters. 3. An IP address can make the development of a site easier if you are not able to develop at the domain name. This depends more on what control panel you are using. Cpanel makes it easy to preview sites that are not on dedicated IP addresses. Plesk makes it hard.
I don't think so, but it might depend on the IP too. Even if you had a dedicated IP, if that IP is a castoff from a spammer, you might have trouble.
I agree with dirty dog. Having a unique ip for your site certainly makes the managment easier and if you want ssl its neccessary. For example, I moved a whole site from one ip to another today and did not have to wait for any dns to change becasue I simply repointed to the new ip address, no downtime of the site at all. sweet. In terms of search engines, I am not sure and am still undecided. I have 1 site on a shared ip with about 200 other sites and it ranks pretty good on google and I applied the "if its not broken dont try and fix it rule". But any new important revenue generating search engine dependant sites go straight on a unique ip though.
The main reason for a dedicated IP is so you can create secure SSL type pages on your site (https://). Another minor reason for a dedicated IP is so that your site appears alone and not shared when a user looks up the dns info on it.