Multi Measures 2.5.0
This measurement multitool has replaced the simple spirit bubble level I obtained from Stanley Toolworks. Multi Measures combines 10 pretty useful tools: Protractor, Ruler, Surface Level, Spirit Level, Plumb Bob, Seismometer, Stopwatch, Assorted Timers, Metronome, and Teslameter. Some are more useful than others, but it feels good to have all of those tools available all of the time -- very handy for leveling out monitors, racks, and more.
Price: 99 cents
Compatibility: iPhone and iPad; iOS 3.0 or later