Coincidentally, I'm reading "IBM's Early Computers" and this book says the first personal computer was the IBM 610 (originally called "Personal Automatic Calculator"), introduced in 1957! It consisted of a desktop keyboard with tiny CRT, along with a typewriter-style printer. (Off to the side was the freezer-sized cabinet full of vacuum tubes.)
Personally, I think it's hopeless to try to pick the "first personal computer", since the term can mean almost anything.
> The IBM 610 was the first personal computer, in the sense that it was the first computer intended for use by one person (e.g. in an office) and controlled from a keyboard.
I don't know if it counts as a personal computer if you need four burly men to pick it up. And the price was rather out of range for home users.
Personally, I think it's hopeless to try to pick the "first personal computer", since the term can mean almost anything.
More info on the IBM 610 is at http://www.columbia.edu/cu/computinghistory/610.html