I totally forgot about Full Moon -- great choice!
If you're near Inman Square, the S&S Deli is great kid-wise. Not exactly a gourmet choice, but the food is good, their brunches are great, and their desserts are enormous (and yummy). If you go for brunch, get there early and bring cash (they don't take credit cards).
Redbones in Somerville (Davis Square) is awesome for kids, too. Loud, but awesome.
Just remembered that my big kids used to love Pho Pasteur in Allston when they were small, but I haven't been there in ages, so I don't know if they're as kid friendly now as they used to be. But they used to let little kids gawk at the huge fish tanks in the side dining room, and that was always a highlight.