I am thinking of building a review website and i was thinking about using php. What language would be good for a website like ratemyprofessor? would ruby be better?
Ruby or PHP? Any modern language will do. Write your code well, and you've got nothing to worry about. They can both query a database, perform if-statements, write session variables, etc. There's not really a big difference for most projects. Stick with what you know, unless you have sufficient need to try something new.
Doug, there's really no right answer here. Jonathan is exactly right about sticking to what you know. However you might like to think about a few other factors:
What does your hosting provider support? If you have a choice, you can shop around for one that supports Django, Rails, or whatever you prefer. Almost every host will provide PHP but may not have the version or database options you would like. Not everyone has the luxury of installing upgrades at will on a dedicated server.
Are there existing solutions that you could adapt in X language? Finding a product that is close to what you require could save you quite a bit of time and determine your language choice.
Who will be assisting you? If this is not to be a solo project, you might consider the available talent and what languages they are most familiar with. How much would you need to outsource, how expensive will it be, etc.?
Best of luck.
Back to school to take a how to program in <fill in the blank>
100, or hire some one here as consultant.
Languages are not important. MySpace uses ASP.NET. Twitter uses Ruby on Rails. Facebook uses PHP. Choose the one you or your coders are most familiar with.
Your questions seem to indicate you are very invested in php, it will do fine for building pretty much any website.
I would recommend exploring and MVC framework like cake php which can help force you in to practices that will result in more maintainable and flexible code.
The one you are most proficient in to come up with something really cool and less error-prone. :)