Casio Illuminator F105W
Most people know of the legendary, everlasting, best bang-for-buck F91W. But if you're looking for that kind of small, thin, lightweight watch I would highly recommend this F105W over the F91W. It's practically the same watch but with better light.
Illuminator is a well known feature of Casio watches. The blue (sometimes green) light can usually be found in many G-Shock or Baby-G watches, but not all standard Casio watches. It is so good for helping you see in low light conditions, and certainly way better than the F91 yellow backlight.
F105W uses the same module with the F91W. It has an Alarm, stopwatch, time display including the day and date. It has a stated water resistance of 30m, but I've taken it swimming without any problem. Just remember don't use the buttons when you're in water!
The watch itself has that classic retro look with cool blue designs on the body that makes it in my opinion better looking than if it were just black resign around the display.
A girl just starting her watch journey. Itty bitty wrist committee member
You forgot to mention the hourly chime! I believe that one pays for the effective back light with an extra millimetre or so of case height and another dollar or two in cost.