I know a few others recommended the Discovery Toys set. I am a Discovery Toys rep and would love it if you bought it through me. A few highlights:
We sell a starter set & add-on sets, so you can buy it all but save the add-ons for future gifts if you want, or you can buy just the starter set.
It comes with a lifetime warranty, so if the pieces break/crack from normal play, you can easily get them replaced from the company at no cost to you (even shipping on the replacement is free and you don't have to send back the old one). even the grandkids can use it!
It's very versatile, with lots of different ramps, feet and connectors so you can set it up in a variety of ways.
My son's preschool had it and, after 20 years, it's still in great shape! I was able to get some pieces replaced that had cracked even though they bought it in the 80's!
If you want it, please visit my website at http://www.discoverytoyslink.com/karenchao or contact me for more info.