Thanks for all the replies. This thread has been extremely informative for me.
The general consensus seems to be that a bit of turbulence is inevitable on any flight through cloud formations like the ones above. However, with a skilled pilot and a certain degree of luck, the worst weather-related turbulence can be avoided. In general, wearing a seatbelt is enough to protect yourself from any potential dangers of flying through stormy weather.
Would I be correct in thinking, however, that there is weather bad enough to take down a plane without any other contributing factors? Aside from hurricanes/cyclones/tornadoes of course.