There are many web host, a few good ones and many bad ones.  They will tell you they have all the options and 100% uptime, which I guarantee is not the case.  I have created a list of the items I use when evaluating web hosts.

I have set up and run a web hosting company myself. We got the collocation space in the same building that Gmail is located in.  We evaluated all of the different web control panels.  We set up the billing software.  We built a website to advertise our services. We got lots of customer.  After about a year we learned that it was better and cheaper to pay someone else to host our sites. 

This article contains all of the knowledge and experience I have gained from the years.

Basic Software Requirements

PHP, mySQL, ftp, log files, email

Good Control Panel

You want an easy interface to manage all of your domains and setting.  If you are looking to run many websites then you need to look for a good control panel that makes it easy to navigate between all of your sites.  Site5 has a great system for multi site hosting.

Good Uptime

You want the servers to be reliable.  To keep them honest we highly recommend Pingdom a website uptime monitoring service.  You can monitor several sites and get all the needed statistics such as uptime and latency reports.  They can send alerts to either your email address or a cell phone.  Depends on how important the site is. 

Good Customer Suppot

This is partilcularly important when setting up a site for the first time.  Once a site is set and configured customer support is not as important.  In the beginning good customer suport can save you lots of frustration.   Most helpdesk should be able to get back to you in 3 to 4 hours.  I wish that number what lower but it is better to be realistic.

Good Servers

Not only do you want the servers to be up but you want them to be running fast.

Back ups