while having a dedicated ip would not do any harm to your site, it is not something that can be described as desirable/necessary, as most sites on the net are not using dedicated ips.
if you are willing to pay for the extra, then you could just go for it.
Just be aware that upgrading a site to a dedicated IP address will cause downtime - it's similar to changing DNS entries, so it needs to propagate with the ISPs.
FYI: You can mitigate and manage this sort of transfer by adjusting the TTL on the SOA for the domain. Have a look at this article for a OK run down on it
While a dedicated IP is most often used with SSL certs due to their restrictions there are other reasons as well but for the majority as has been said already then a dedicated IP is not required.
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