I decided to switch hosting companies after being with Verio since 1998. Verio's pricing for adding additional new websites was too expensive with the other alternatives offered. Their service was excellent, but their multi-site offerings were not competitive.
After researching hosting companies, I decided to go with:
Total Choice Hosting
They have relatively inexpensive hosting plans and I am in the process of moving several of my websites over to them from my prior host Verio.
Part of the consideration in selecting Total Choice was the cost per site, compatibility with scripting and special requirements of my existing sites, reliability, response of customer support, and other user's reviews. They also have an online forum for support where they respond very quickly and there is a lot of searchable information immediately online through the forum. Each hosting company will have various subtle differences in they way they implement hosting software and their user forum saved time in converting my sites by finding prior info on the problem and what the solution was (If you are designing a new site, you won't have any conversion problems). I have transferred 5 sites so far with minimal conversion problems.
I use Macintosh for design work and have rarely run into a problem with either my past or current host...
For domain name registration, there are many inexpensive possibilites including what the others have already mentioned. I would add MyDomain.com to the list.