What to pack?

Earlier this month, I posted about my intended gypsy lifestyle for the remainder of the month. I will be leaving Detroit today, and will not return until December 28/29, depending on flight loads. Above is a picture of (a new version of my) trusty silver suitcase. It has traveled with me for over 40,000 flight miles and 3,000 road miles with me this year. It's a the Swissgear Zurich 20" pilot case in metallic pewter from Target. Before I was the wife of an airline pilot, and traveled by air infrequently, I would buy the super-bargain luggage from department stores. For $69.99, you could get a 5-piece set in a myriad of colors. Perfect, right? It only took about 3 trips by air before the wheels and handle were shot. I decided that I would invest in a great carry-on bag, since checking luggage on a standby flight is a non-rev faux pas.

This morning I'm flying to Portland, OR. The typically temperate December weather that I remember as a child will not be the reality this weekend. Heavy rain and snow showers are predicted tonight. Salt Lake City weather will vary from the 20's to the 4o's. And I won't be in California for 10 days, and the forecast out that far predicts average temperatures in the 60's to 80's. I have very limited space to pack for very different climates. For a girl who's a mad travel junkie, here's what I'm wearing and packing in my limited space:

On me:
Black half-zip sweater
Long sleeved tee
Black casual trousers
Two pairs of socks
Keen Ashland shoes (comfortable for walking long distances, but all-weather)
Parka, gloves, scarf and hat (which stuffed into a tote bag make a decent pillow)

In the laptop case:
Tucson, my trusty laptop
Meds, cold remedies, motrin, kleenex
3 magazines
Ipod and headphones
My quart-size zip-top bag with my less than 3 oz. toiletries
Snacks and gum

In the suitcase:
1 pair of jeans
1 sweater
4 short sleeve shirts
1 dressy shirt
2 shades, black and red
Underclothes and socks
1 dress, with hose and slip
1 pair dress shoes
Toiletry bag with dry makeup, floss, toothbrush, etc
Glasses in a case
Small Christmas gifts

During the summer, I'll include my swimsuit and some capris. I've almost got this packing down to a science. Any other tips for packing in with limited space?