I store all of my centers in 3-ring binders-the really, really, really big ones and keep my materials in insertable page dividers. I organize the activities by subject and by unit within the subject, and I've found that this is a really easy way for me to keep organized.
I also keep all of my task cards in Ziploc baggies, so they store nicely in the dividers.
I'm pretty selective on the centers/station activities that I actually have out and available to my students. There are always a handful of activities for our current topic, as well as a few review activities from different units, but I don't like to have too much out at a time. I organize these into different tubs that I bought from Really Good Stuff. The were pricy but worth every penny. I LOVE being able to stack things neatly!
Inside my station tubs is everything my students need to complete the station(s). I like to include sleeves for recording sheets to save on paper and copies, so I have included wipes and dry erase markers in any storage tub that has a recording sheet.
I can't wait to read everyone's ideas, so be sure to join the party!