For those of you who want to know a little more when talking to sales people:
Waxed
skis have what is called double-camber. If you put the skis with
the bottoms together, the tips and tails will touch and there will be a
big gap between them in the middle. If you try to squeeze them
together, it's relatively easy at first, but it takes a great deal of
effort to get them to touch right in the middle. Those are the two
levels of the camber. When you have your weight evenly distributed on
both skis, they should only compress to the first level, leaving the
center part or the 'wax pocket' not touching the snow. So when you are
gliding, the wax is not dragging on the snow. Then when you shift all
of your weight to one ski to take your 'kick', it compresses the ski
through the second level of camber and drives the wax into the snow,
giving you the grip to push off for your next stride.
This is
tested when choosing skis with the 'paper test'. Place both skis on a
smooth flat surface (some shops will have a sheet of glass available
for this). Stand on both skis with your weight distributed evenly.
Someone else should be able to slide a piece of paper under the ski
from 12 inches or so in front of your foot back to just past the heel
of your foot. That's your wax pocket and where you put your kick wax.
Some people mark this on their skis. Then when you shift all your
weight to one ski, the pocket should compress and the paper should not
be able to slide at all.
If the skis fail the paper test, try another pair.