Each and every Search Engine Optimiztion professional looks server selection for beginning of any project. There are lots of factor search engines consider that your website ranking could be affected by your webserver.

Uptime : This is major factor affect your website's ranking.

Name Servers : this can also affect your website's ranking if share your name server with a large number of spam sites.

IP Classes : You could be penalized if your site is mixed into a bad neighborhood.

Sharing an IP Address

Response Time : If your website take time then it will take longer to read each page and spiders have to move all over the pages before cralling.

301 Redirect Capabilities : 301 redirects help to move without www domain to www.domain.