A few years ago, I think it was before I even had Gonzo, my grandmother bought Miss Crab the most fantastic set of Lincoln Logs from FAO. No craptastic plastic, all wood. Completely traditional set.
It sat unused for a while - Miss Crab is of a special temperment that lent itself to mega tantrums when she could not master something immediately. Heh. But now Gonzo is 3 and Crab is 5.5 and Lincoln Logs provide hours of happy play. As long as Gonzo does not knock down Crab's fort.
The big wood box is perfect for easy clean-up. The kids will use all of their little farm animals in very complex pretend-play that also involves Velociraptors and T-Rexes. Gonzo, as I type this, is giving the animals some sort of cheer that involves shaking maracas. Of course.
My brother and I had "lock-blocks" or maybe Loc-Blocs? I need to look that up. It was not the big chunky ones but it was not legos. Sort of an in-between. We played with those endlessly.
Ed: I am laughing so hard - I just found this great Wiki about Loc Blocs. Read it to the end and see why my brother and I will need years of therapy. Ha!