I would not register my domain and host at the same place. Let the registrars register and the hosts host
Really, when a registrar hosts for you they usually do not give you the features that mosts hosts do and they plans usually are not as attractive.
When you register a domain with a host you usually get less controll over your domain.
I would register with godaddy.com or cheap-domainregistration.com (i use and like both). And I would find a good host. (Cough cough).
As for space and needs for the site you are creating, you can probably start off small unless you have a ton of graphics on your site.
Our smallest account we sell is 300Mb disk space and 5Gb traffic. Most sites can be hosted under those specs with no fear of going over.
Look around and good luck!