I use a rubbermaid container (the long kind that fits under beds) for a water table inside. Outside, I have a mini pool that can be used on it's own or attached to the slide on the structure. I just use it on it's own. I had a water table (can't remember the brand, it was just a cheap one from Zellers) but I found they didn't really play with it. So I sold it and now just put them in their bathing suits and let them play in the pool or around the yard.

I have a small yard and have a big play structure, the pool, a diego ship, picnic table and than of course all the toys and ride on's. I unfortunately don't have room for a sandbox (oh darn! lol) but thankfully 3 playgrounds are super super close so we just walk to them and play.