IP Adress Hype

Just wondering is there any big difference between ex: one wordpress per one ip address or five wordpress blogs per one ip address.

Not really, the domain name is the most important part -- The interlinking of blogs on the same IP is fine if the content is unique and you are getting a large amount of quality links. The Hilltop algorithm doesn't qualify as much for a site with 5 blogs, when you have 1,000s of blogs, that's an issue but it still doesn't matter if you build authority