T-square has handed over some of the considerations and there are more. Why not hunt around on ebay and get yourself a cheap used pair of similar skis, K2PE's for example, in a longer length and when the snow starts falling get out and demo a range of different style/length/width skis.
FWIW, I have to travel to ski so multiple skis are not an option for me. Have managed to tick off 16 different mountains in Canada and have been travelling to Japan for the last couple of Winters, ski here in oz every once in awhile if the oppurtunity arises. I have been on Head Monster im77's in the 177cm length for the last 5 years. Overall, I would have been much better off on the 88's but the only time I have felt that i needed wider and longer has been in Japan where the Powder is relentless. Last Winter, I was hiking out of an area with a couple of blokes, one of them had Hellbents and the other had Coombas, we got to chatting about our skis and i decided it was time to try something bigger. Demoed some Mantras and ended up buying some to replace the Monsters as my travelling ski. There are better skis around for sole use in Japan but since i plan on poking around the US when the dollar allows, I purchased the Mantras (184cm) as my do it all ski. i reckon they would be perfect for allround North American skiing (excluding the park).
My point (finally), have a look at whats available in the all mountain 50/50 category. If you want park capability then that will narrow your search parameters even more. consider older models and ebay, its not hard to put together a quiver for a fraction of the price of latest model skis.