Everything you read will tell you that if you change your ip address, it’s going to affect your ranking. One of the reasons I’ve read is because computers keep track of numbers for ip addresses, not of names for domains.
I’ve never really believed this because logically it doesn’t make sense. I mean, is google going to punish you just because you were unhappy with your hosting company so you changed? I doubt it.
Anyway, today I read a forum post about it and there were tons of people saying that they have switched hosting companies, or their hosting company switched their ip addresses, or something happened to cause their ip address to change and nothing happened. Their pagerank didn’t go down, their rankings didn’t change. Nothing happened.