DO NOT even utter the words you are 'sad' for feeling motivated by having nice shiny new cleaning stuff - hey, every monday nearly I buy something that will magically transform my home - today a real lambswool duster... mmmm.... fluffy.... (dog ate last one)
Last week it was a bucket, and sponge, and car cleaning stuff. Whenever I finally get motivated to clean the car, we have no stuff to do it with! So now we have the 'car' bucket.
Bunnings has great big 50l tubs with ropes on the side that are perfect toy baskets, because they are reinforced. As you probably already know, I have lost many plastic 'tubs' to the kids who love to sit in them instead. I've had these now for a year and no breaks!
Excellent idea about the swimming tub. Don't forget sunscreen!
Another idea I did recently was to grab an old backpack, and go through the kids clothes, and anything that I would usually send to Life line I made up a couple of outfits, then added a nappy, some wipes, sunscreen, mossie coil, pens etc and now that bag lives in my boot of my car. You just never know when you might need it! We recently did a 'quick' trip out to the IL's, and I had NO clean clothes, no nappies, nothing with me, thinking we were just dropping past. So this is a just in case you never know bag.
Here is something from an older thread that I wrote:
"I also have an "Action Station", which is our old baby change table. It is just as you walk in the door. Baskets for everyone in the house on top, with calendar and incoming mail. (Technically I should open mail, mark on calendar event or payment, and go and immediately file the paperwork). Pegs for "school notices/excursions/tuckshop" stuff. Key hanger (I am a shocker for losing my car keys). Then underneath, on middle tray, all school bags, 'yoga bag' (cobwebs and all), beach bag etc. Then a basket underneath for school shoes. Also a 'four hook hanger" off the side for school jumpers/coats. Also an "Out Going" basket, for all those things you borrow/get/need to give back to friends, family. For eg, my mum gets parcels to our house. So I put it in the OUT basket and she knows to check there everytime she drops in. It is really, really handy, especially for school notices and shoes and stuff. But also is the worse place for dumping stuff.
Just have to keep on top of it and clear it out/take action every week. I find the baskets really handy because if there is something I need my DH to do, (handyman stuff "BLUE JOB!"), I write it on a sticky and put it in his basket. (Fix knobs, leaky tap...) He usually takes more notice that way than me nag nag nag."

I think the main motivations are to not to try to do it all in one day. You will end up with more mess than before. Start in a corner, and slowly, slowly, you'll get there.
Having a garage sale is a great motivation to declutter!