fof, welcome to EpicSki!
Your weight, turn length, terrain, and snow conditions will all effect the length for a particular ski type. The ski type will determine the range that you should try. Unless you're racing DH on the world cup, you're not likely to be 190cm or above, though. Many of us here on the forum have gone through this transition.
Interestingly, skis are using characteristics other than length to provide structural strength and integrity. For example, the Atomic Metron:b5s that I ski use magnesium channels from the mid-ski to support the tip and tail. As a result, they can be skied much shorter (at 185lbs I ski them at 162cm. So far, I have not been able to find a speed limit, even when I push them about 45mph). Other designers use different means, and the different uses of the skis imply different lengths as a result.
In a slalom ski, you might ski one in the 160 range, as Phil mentions. In a GS ski, you might be a bit above 180. Typically, I agree with Phil: you're likely to be in the 170-180 range, especially given your weight and my assumption that you like to get up a head of steam. But, turn shape, typical terrain, and prevailing snow conditions will play into that selection, too.