Which is more important when choosing a host, price or reliability?
reliability over price
price is meaningless if detached from reliability.
When building any commercial website it, is always a good idea to spend a couple more dollars a month if it means better support and reliability.
Its depend on your hosting needs, is it a mission critical or eCommerce web site? If it isn't then I'll go for price over reliability.
reliability should definately come before price.
From a company perspective, I would hope that "reliability" would be vitally important. It is hard for us to compete on price with Joe Blow who runs his hosting business out of his bedroom in his underwear. We do compete very well when service is a factor as we have a proven track record.
You need to define first what is important for you. If you can afford a downtime from time to time then go with cheap host. But you can not expect to have a service with good uptime and realiable support for a dollar a month.