Several years ago I became inspired by an agent I worked with who only ever traveled with carry-on. She went to Africa for 2 weeks with a little backpack. After that I started to travel that way as much as I could and I almost always go with carry-on only, even when I went to Europe for 6 weeks. Business or pleasure, tropics or the poles.
There are only 3* things you absolutely need to take when you travel:
1. Tickets or other confirmation (like e-ticket receipt)
2. Photo ID
(ALWAYS take your passport it's the ultimate piece of photo ID
- also remember any travel visas or other documents you might need)
3. Money - a bit of cash and a credit card. Whatever you forget you can buy while you are there.
*plus prescription medications, if you have any
This should go without saying but NEVER check-in any of the above items. Anything that you cannot easily replace, don't check it in. I can't tell you how many times I've taken missing bag reports from passengers and they tell me they need their heart medication - that they checked in...
Everything else is supplemental.
Once you discipline yourself into traveling with carry-on you will never go back, especially if you every fly standby. You will be able to run to that tight connecting flight and make it, catch the first bus from the airport while others are still waiting for their luggage, and get in and out of customs fast.
Get a carry-on bag, pack your stuff in it. If it doesn't all fit you have too much stuff.
Here is a fantastic website: www.onebag.com
Spread Good Standby Karma for fellow non-revs.