You have probably started organizing your pictures by now...lots of good suggestions so far.
I would want to suggest that you have to start with one important question first before you start the "not trivial" task of picture organization. It's a lot harder to undo what you have do wrong. The most important question is: What is the criterion for organizing your pictures? Most people use their camera to shoot events and in this case you can do year/month/event. Other people shoot geographically and for them it makes more sense to do Continent/Country/City. So, it really depends on how you plan to use your structure. Here is an article that might help you with this question:
Divide and Conquer for efficient picture organization
I believe that an efficient folder structure beats any tag collection by far (in most cases). At least that's what I've been using for years with great success. Here's another article that will help you with that:
Organize your pictures in 5 easy steps
And in case you're wondering about tags versus folders you might find this helpful:
Tags vs. Folders - the great debate
I hope this helps.