I use namecheap.com for the bulk of my domain registrations.

I can't comment on customer service as I've never had to call them. However, I've not had any problems with their website and interface.

The bulk of my domains are there, but i don't use their name servers for most domains.

Have also registered a couple domains via bluehost.com -- bluehost.com is a large web hosting company; while I haven't gone live with any of my domains there, I found their customer service to be extremely helpful.

As far as web hosting goes, I'm looking to move some stuff over to bluehost that would be best suited for the type of service / environment they provide.

Otherwise, I have a couple Apache servers that I run as I've been keeping my hosting "in house" - I have a couple here, and also in data centers.

With data centers, I rent the rack space and they provide a static IP with high-speed internet connectivity. Each has pro's and con's as I must maintain my equipment in the data center and physical access is limited; the servers are highly redundant between power supplies, RAID hard disk setup, items such as hard disks are hot swappable, etc.

Lot of different options - if you're looking for domain reg + hosting, it may be easier to pick one company that offers both, but look for quality web hosting and pricing that meets your needs.