You will only need private (or personalised) nameservers if you intend to resell hosting, using their reseller plan as your source of suppy. If you're not going to sell hosting, then their default nameservers will serve you just fine.
•AussieHost.com• Aussie Bob, host since 2001 • • Host Multiple Domains on Fast Australian Servers!! •
Bob is absolutely correct - however, remember that private nameservers purpose is ultimately to create an illusion - being - that you are your own provider.
So, if youre reselling hosting, you want your customers to believe you are the ultimate provider and also, you want to "protect" your source so your customers do not go directly to them.
If you want to create that illusion for whatever reason, you should get your own nameservers.
ie - if someone does a whois on your domain (billshosting.com or whatever) - what information do you want them to see or do you even care. Based on that, you can determine if you want or need your own nameservers.
From experience, most resellers insist on their own nameservers and it shouldn't be a problem setting it up on the server. As the others mentioned, you shouldn't be too concerned about it if you are not selling hosting space.