It depends on your current capital and your business plans.
If you do not have enough money to start out big, then go for a reseller. But, resellers can have its shortcomings. For instance, many customers like to see a host name's branded in the nameservers, and seeing someone else's name in the nameservers might discourage them. Also some resellers, don't come with sufficient space nor bandwidth, and if they do it will be costly.
But, if you have enough money I would suggest a dedicated server. Dedicater Servers allow for complete root access. But, there are many things you have to take in affect. For instance, downtime is something every host might have to go up against. Breaking your goals, because dedicated's can be very costly, and the average starter hosts can sometimes not maintain it.
I would suggest
www.surpasshosting.com for both resellers and dedicated's.