John Muller from Google spelled out in Twitter that Shared IP addresses are fine for search and if he is to be believed lots of hosting or CDN environments use those shared IP addresses. Content Delivery Network (CDN) is a service that can help the static content on your site. According to John, using a shared IP with other web sites, even if some of those sites are slummy is fine.
Though the above thing isn’t new and has been covered many times, but in rarest of rare cases Google may ban a whole free host or co.cc path. Time is to concentrate more on the websites, content and how to build your site, rather than your IP addresses.