Flora and Ulysses
The story is adorable and the illustrations perfectly match the sentimental, slightly melancholic mood. I know I should be suspending my disbelief (magical vacuum cleaner, squirrel with the gift of flight etc) but it did bother me that the squirrel could suddenly type in perfect English... I don't know why I balked at that particular aspect but it did bug me. Not enough to spoil the book for me, though. Flora & Ulysses won the Newbery Medal a few years ago and it's not hard to see why.