1 and 1 Internet

I regularly use two domain registration services, I started with 'GoDaddy' and have found them to be excellent, but when I discovered that they don't really do '.co.uk' domains, I had to find an alternative.
I have to say I have been very pleased with 1 and 1 for domain registration - they offer a cheap and comprehensive service with easy-to-use front panel which allows you to change settings such as DNS. They are also helpful when it comes to getting support.
However. the reason I am most impressed with them is they are turning into my most active affiliate. The payouts are relatively small, but come in quite regularly - I even had two notifications today! The reason they are successful for me as an affiliate (I believe) is that I think they actually provide a decent service - and they really do offer competitive prices. So many other affiliates I try to promote are not really competitive price-wise. They offer big incentives, but you can't really put your heart and soul into promoting them because you can't in all honesty say they offer great value.
So hand on heart, especially for UK domains, if you are looking to buy a domain name or looking for a comprehensive hosting or email package, try 1 and 1 (they are not limited to UK domains by any means, but that is the reason I started using them in the first place).