My favourite registrar is:
www.namecheap.com
Because they offer free whoisguard with a new registration and after the first year, it's very affordable.
But i have an interesting style, using namecheap as only registrar, not name server. I use
www.xname.org as the name server. They are totally free.
Why i like them? Because they allow sub zone delegation (which is not A or CNAME), while almost most of the registrars do not support this feature.
What is sub zone delegation? If you want to give a portion of your domain name's control to someone else. Like you have abc.com.
You'll give myfriend.abc.com total control to your friend at totally another name server. Delegate myfriend.abc.com to other name server's with NS records and forget it. Your friend can independently manage that portion in his name server.
As registrars if they can support this and let me know if you find any
By the way, does Linode's DNS support this?
Regards,
cplnd