Wildflower -- your travels sound marvelous, and I'm envious!
For putting together your lists, you might consider checking into the various birding software packages available. I don't have one myself, but two names that come to mind are Thayer and Avisys. And neither one would be difficult to locate, I'm sure.
The kind of lists you keep are completely up to you. For myself (with only North American birds, unfortunately), I just jot a note or two in my field guide, date, location, etc. Others keep much more detail, like habitat, weather conditions, etc.
The important thing to remember is that it's your list and you can do whatever you want with it. People keep all kinds of lists: life, world, state, county, backyard, seen while in the car, etc.
A good source for birding books and guides of all kinds is the American Birding Association. They have a very wide-ranging bookstore and I believe everything they have is available for ordering on-line. They have software packages, too, I think. And you don't have to be member of the ABA in order to purchase, although I think they offer member discounts.
My last question for you is -- with all your travels, what birding have you done in the US? If you have traveled as extensively 'at home' as you seem to do internationally, I'll bet your 'domestic' list is awesome!