is that a good thing ....

Would you reg a domain and host it with one and the same company?
Say sibername.com is a good domain registrar and they provide not bad hosting services.
And I think of using one company for running my company. 

I think it doesn't matter. If you are sattisfied with their service then just host your site there. Otherwise there are plenty of options :)

Thanks for your input, Nikolas.
Any other opinions?

As purchasing a domain of GoDaddy and using there Web Hosting Service? I personally would. I just wouldn't do it if the company is recently new and has no feedback.

never host with godaddy :)

there are a lot of web hosting provider selling domain registrations, but I there is no domain registrar selling powerful web hosting :)

Why wouldn't you host with godaddy?

the hosting is terrible, a lot of features are disabled. search google for "experience godaddy hosting".

I registered ~100 domain names with them and move them al out (the panel is very slow and you need to search coupons all the time to have a fair price)

I almost learned the hard way why it is never a good idea to register and host domains with the same company. When I fired my webhost recently, they made it very difficult for me to transfer the domains to someone else. Email clarifications were mysteriously lost, passwords didn't work and they made what should have taken hours, take almost 3 weeks.

They had me and they knew it. It was childish of them and bad business but because of the way domain resellers work, I would have had little recourse if they had kept at it. Some of the domains were transferred only because there was someone at the primary registrar who helped me even though their company policies prohibited working directly with end users as their "customer" was the reseller not the customer of the reseller. There are tons of horror stories out there about domain hosts/registrars holding domain registrations hostage.

I had heard this same advice when I was just starting out and thought "Naw, this is a good company with a good reputation - it won't happen to me and besides I will save a few dollars." I just count myself lucky that it wasn't worse.