I build database-driven web sites. Previously I have used Perl or PHP with MySQL.
Now I am starting a big new project, and I want to do it in the way that will result in
The latency of the network is by far the greatest determining factor in this argument. In fact, network latency is so much of a factor that it renders language considerations rather unimportant from a performance issue. So...go with what you know. Use the language that you are most comfortable and most productive with and other considerations can be worked out as you go along. Now, that said, it's always fun to try new stuff and learning new things can become an obsession, so if the project is a personal one that allows you the opportunity to experiment, well, by all means.....