clarification before buying a internet static IP address

[vuthecuong]

I need from you advice before doign things.

Up to now, I have a home web server using free DynamicDNS service of 
dyndns.org.
With it, I can access directly to my home web server from ouside through 
Internet.

Now for some reason, I not want to use DynamicDNS service anymore.
So I tend to buy a staticDNS from domain reseller.
Suppose that I only buyed a domain www.mydomain.com with internet static IP
address : 74.52.8.254, not buyed hosting service from that domain reseller,
can I be able to set up my own DNS server (in my home PC server) so that 
I can
browse directly to my home web server by typing www.mydomain.com
into address bar of firefox, opera?

i meaned, in other words, in order to host one website so that in can be 
"seen"
all over the world, I have no way but must use external hosting service?
Tnx
Sorry for my bad English