The best language is whatever language the people developing the software in are going to be most comfortable with. From what you describe, the preference is 1) Ruby, 2) Python, 3) Perl. Therefore Ruby is the best language to do it in, then Python, and finally Perl.

All of the three languages are capable of making websites with, and all have tools to help you out, so that's not a deciding issue. Apparently, your groups finds an OO structure important, so you should choice a language that gives you such an OO structure. If that happens to be Ruby, Ruby is the winner.

Abigail