Siam N° 10
I skied a few weeks ago at Crystal Mountain here in Washington and demo'd a pair of K2 Recon skis, part of that company's Apache series (www.k2skis.com). We had ice that day, some groomed runs, and some fresh, pretty deep, semi-powder. And I thought the Recons were great. They had good float in the soft stuff, tracked well at speed, and gave me a lot of confidence when busting through uneven snow. I thought they were perhaps a bit sketchy on icy stuff, but that could be because the edges needed sharpening. But generally I thought they were great skis.
You can find a pair for about $650 without bindingsmaybe less on eBay or at an end-of-season sale. Take a look as well at the K2 Apache X's, which are designed for similar all-over skiing but are a bit more forgiving in the torsion box, which might be desirable in a lighter skier such as yourself. The X's go for about $350, sans binding.
Salomon also makes a good all-mountain skithe Siam N° 10 ($720 with S810 binding; www.salomonskis.com). These also are a women-specific ski, meaning the flex and sidecut are tuned to better accommodate how women ski. They're also are a fairly light ski, so you can ski longer with less fatigue.
If you can, try a few different skis out at your local resort. This time of year you can probably even just buy the ones you like, right from the demo shop, at a hefty discount.
For a look at the year's flashiest skis and 'boards, check out Outside's 2006 Hot List.