My primary criteria for travel packing isn’t how long I will be gone, but whether I am going for business or personal travel. (Business travel requires dressing up and that involves lots more clothes for me than personal travel.)

For a 20 day trip for personal travel

In this bag: eBags Weekender Convertible
Clothes
-Black pants does double duty as dress up or day stuff
-Khaki pants good generic color
-Skirt (black or grey) (or a kilt for the boys)
-3 short sleeve black tshirts for layering or for warmer temperatures
-1 long sleeve black T
-2 white tshirts
-Black V neck sweater
-Red button down shirt or light cardigan
-Socks (smartwool)
-Undies (ex officio magic undies)
-2 scarves (I use the pashminas-useful as a blanket or a scarf)
-Jammies/hotel wear
–Barn Jacket – lightweight and ScotchGuarded for water resistance
-Crocs (for the plane)
–Keen shoes (for walking)
–Black Sandals
-Swimsuit

Other things:
Toiletries:
-Shampoo (travel sized x2 as my hair is very long)
-Conditioner (x1)
-Toothbrush/toothpaste
–soap
-Bandaids
-Other miscellaneous goops
-Lotion SPF 30

Toys:
–Computer/power supply/bluetooth keyboard/bluetooth headset
–camera/charger
–Solio/cables
-Treo/cable
–Silk Sleep sack (good for both hostels or when the harsh chemicals that they wash sheets in hotels in burn your skin as they do mine. This is also good for adding another +10 degree rating to your sleeping bag without adding a ton of weight or having to buy a new one.)