I grew up with Lego. I love Lego -- the older stuff anyway; the newer bricks are too specialised -- and what's amazing about Lego is that it is almost impossible to destroy a Lego brick. I still have all my old Lego and all of my dads' Lego from when he was a kid. They do get a bit grimey and dirty after a while -- thankfully they're easy to clean in sudsy water and they'll look good as new, even 40 years later.

Buy it once and give it to your kids' kids one day.