Actually, I just found this article , which points to solving the problem. It's a variable called "word_separators" in Sublime Text 2 > Preferences > Settings - Default

I'd also like to see this addition. Maybe do something like TextMate, where it allows you to specify (via preferences) what characters would be included in a selection when you double-click. That way, the user can add extra variables (like the $ sign if they use PHP, or the @ sign if they use Ruby/Rails).