When people ask me for career advice your question is one of the first questions I ask them. I don't think anyone can answer this question for you; I think you have to decide for yourself whether focussing on depth or breadth is more likely to meet your career goals.
When I last changed teams I had two opportunities: to work on the XBOX developer tools team, or to work on the C# compiler team. I realized that it came down to breadth vs depth. On the XBOX team I could work on security systems one day, audio systems the next, video, networking, hardware interfacing, you name it. Sure, some people are experts, but everyone has to know a bit about everything. On the C# compiler team I could dive into one language and one compiler and really understand the whole thing in depth.
I gave it a lot of thought and decided that I was more tempermentally suited to being an expert on one thing rather than a dilettante at many. That was a good choice for me, but it might not be for you. Some people are highly successful knowing a little bit of everything.
My advice therefore is to turn the question around. Figure out what kind of person you are, and then see if your company has opportunities for someone like you. If not, find one that does.