I just wanted to thank everyone who recommended "A Tree Grows in Brooklyn", as I've just finished reading it for the first time and loved it! That's the first book I've found from my list of "must reads" from all of you here on the Bookworms forum. Next is "The Wild Trees" by Richard Preston. Still waiting for the library to get a copy of "On Basilisk Station"...
I've also been reading books that have been assigned to my 6th grade daughter so that I can help her study them by posing her questions. Turns out they are great fun for an adult, too!

"A View From Saturday" by E.L. Konigsburg was really good, as are the books by Jeanne DuPrau such as "The City of Ember", etc.