I've always pretty much been a dedicated server guy which means I can pin the CPU all I want, etc and not have to get yelled at by anyone but my users & clients ;)
But obviously most people use shared web hosting and there have been a lot of posts here lately about people getting charged extra (a lot extra) by their hosts for using too much CPU. Many can't afford the cost of a full dedicated box; virtual dedicated servers are another option that is much more affordable.
Looking around on the 'net I see prices that range from $27/month - $99/month for a VDS with anywhere from 50GB-2000GB of transfer, 5GB-60GB of disk space, memory 'burstable' to 2GB, etc.
There are downsides such as the fact that most of these options require you to self-administer the VPS, but with tools such as Web Host Manager that's not really that hard. And you might learn a thing or two by being a bit more involved with the administration of the server.
Also you should look into the specific contract with your host to make sure you are allowed to pin your share of the CPU all the time.
Anyway it seems to me anyone running dynamic sites should consider going virtual dedicated so you don't have to deal with getting in trouble for CPU hogging, plus you get root access so you (or your programmer) can install whatever programs you want.