You can start from the cheapest dedicated server from a reliable host and upgrade as your needs increase in terms of resources and bandwidth. This will save you lots of money which you can channel into other important activities such advertising and link building.
Although you can go for an expensive server if you have lots and lots of people already waiting for your website to launch.

You can also consider starting from shared hosting or VPS.
It depends on your plans. Your plans will dictate the specifications you need. As the proverb goes, it is only the stomach that knows what will satisfy it.

Biodun,
OluOmo 1 of Support, Hostmot (
www.hostmot.com)