360: Heed Rusty's advice. In addition to being a photographer (and Lightroom instructor), I've been a computer tech/nerd since the days of CPM, 8" floppies and punchcards. One thing I've learned over the past 35 years with bits and bytes is that drives will wear out and fail. From experience, I replace them every three years (or at least not in the critical workflow), replacing both internal and external. That being said, if you let LR organize your images into [Year\Year-Month-Day] format (seen as 2011\2011-10-20) then you'll have SO many positives going for you down the road, starting with ease of migration to new media.
1) Your annualized images will be organized by day. Most of us us calendars for our work. If you need to find a particular day's session, get that date from your calendar/planner and scroll down in your LR Folder, Explorer or Finder window until you find that day's images by its folder date. Simple. That's how computers think - sorting by numerical then alphabetical. If you follow #3 below, this will be the only time you look at your folders again.
2) By having your sub-folders in ONE folder (i.e. "2011"), when you, as Rusty says, migrate that folder to a new drive, it's just a matter of seconds to point LR to the new location for those assets. Again, simple. If you don't use one master folder and they're all in different folders, then when you copy those individual folders to a new drive you're condemned to spend HOURS reconnecting Lightroom with the myriad of individual folder locations. If you don't believe this, try it and see. Painful. Be good to yourself and use ONE folder with sub-folders and you'll love LR life.
3) If you use COLLECTIONS and Collection Sets (containers for collections) to organize your images, you've eliminated the drive wear and tear of using folder organization because you use the LR database (speedy, fast) instead of the computer's base operating system (slow and tedious). Now you have a whole new world of unlimited access to creating virtual copies of your images for versions (which take up virtually no sizable disk space to speak of relative to copying CR2s,NEFs or DNGs), as well as unlimited versions of sets of your images, great for doing breakouts of wedding image sets (bride's album, groom's mom's album, etc.)
Heed Rusty's advice and use one master folder. Then make collections on EVERY import. It's the only way to go, and it conserves on drive space and usage.