I recently made the jump from C++ to C#, and while that may not be quite the leap from web to OOP, it was still a great opportunity to learn something new.
(I can't even imagine an argument against learning new languages and programming styles.)
I was lucky enough to be able to move between departments easily enough. If you are able, request a switch to another and give that a shot. Be ready however for the switch. Your head will be buried in books and websites (perhaps a development community site) for most of the day, and you'll definitely feel like you're always falling behind in your work.
Inevitably, it doesn't matter because you'll come out more marketable, and at a time like this, that's all that counts.
One last great reason to try out something new, if you decide you like both, you'll be able to bridge between the two in your applications and fully understand dataflow from front to back ends.