I've seen lots of packing lists on the internet. They all do a lovely job of putting down exactly what you need for particular destinations. They're quantitative. They'll help you squash your possessions into a backpack that will get on the plane without extra luggage charges or hassle.
But I'd like to suggest a different way to tackle your packing. Divide your possessions into necessities, and things that will enhance your travel experience.
I'm hard line on this. When I worked as an investment banker in Eastern Europe I would head out for a two-week tour of duty with just a carry-on daypack. I never got held up by baggage delays and since I was often on the move for most of the two weeks, I didn't have to keep packing and unpacking.
First necessity; paperwork. Passport. Driving licence (if you're going to use it). Insurance details. Phone number for banks and credit cards. Money, cheques, credit cards, etc.
Second necessity, clothing. I've managed a week in Istanbul with one pair of trousers, two shirts and five changes of underwear, and I was perfectly presentable. I *did* take an excellent big pashmina though, which was a shawl when I needed warmth and a headcovering when I wanted to go into a mosque. Find clothes that don't need ironing, that dry quickly, and are not going to show the dirt. (A white suit is fine for Martin Bell, but I bet the BBC pays for his dry cleaning.)
Okay, you might want to have the option of lighter and heavier clothes to deal with different temperatures, particularly if you'll be away for a while. But be sensible. Use layers rather than taking two different wardrobes.
Third necessity, toothbrush, toothpaste, SPF 35 cream (I'm very fair, and burn easily) and soap. A tiny square of towel.
Now, let's think about what could enhance my travel experience.
More clothes? No. Just more to carry, more to think about in the morning, more to pack and unpack. (Okay, this would be different if I enjoyed dining out in posh restaurants; I'm much more likely to be drinking a cup of tea with the market porters in a little han near Tahtakale market, or eating a bowl of soup with nuns in a convent on the Camino de Santiago.)
Oh, maybe a swimsuit. There's nothing like a swim for refreshing tired legs. And it doesn't take much space.
A camera? Yes, certainly - since I'm a photographer as well as a writer. In fact, I prefer to carry two - my regular Pentax SLR, and a little compact for situations where I don't have the time, or don't want to get the SLR out with all the attention it might attract. And lots and lots and lots of media (SD cards). Not forgetting the charger.
A notebook. Absolutely vital for me when I'm working, but even when I'm not, I like to be able to scribble down odd thoughts. Recipes for food I've eaten - I collected a lovely recipe for apple tart from a farm where I stayed in the Montagne Noire in France, and I have a good recipe for fasulye, Turkish bean stew. Oh yes, lots of really good pens.
A laptop? Actually, I rarely bother. Pen and ink is more flexible. I might, if I were going on a much longer trip - and I'd probably get a really tiny one.
Business cards - well, these I do travel with. Because when I meet interesting people I'd like to be remembered, and stay in touch, and this is a good way of doing it. I have cards from moo.com with my flickr photos on the back, so they're fun and even a nice little present.
And one very important thing that will really enhance my travel:
SOME SPARE ROOM IN MY PACK.
Because I can guarantee I will see something that I want. Probably not a tourist souvenir. In Turkey, I bought three zurnas; they are beautifully made instruments, and ear-splittingly loud, and I will learn to play them as soon as I can be quite sure my neighbours have gone out. In Bulgaria, I bought a set of bagpipes and one of the nicest, most soulful whistles I have ever played. In Poland, I passed an art exhibition in a gallery near the Bristol Hotel at eleven o'clock at night - the next morning, I was there at the opening and came back with a huge oil painting. It's still on the wall in my study, and I can see it as I'm writing this.
(Not recommended as a souvenir, by the way, is monosodium glutamate. Someone I know bought quite a lot of it in Hong Kong, as it's a common ingredient in Chinese cooking. Nothing wrong with that; I've bought sumac in the Middle East, paprika in Hungary. Trouble is, monosodium glutamate is a fine white powder...)
Apply these guidelines to your packing and you'll soon be able to resist the temptation of adding another sweater, a 'just in case' pair of formal shoes, whatever. And you'll travel the lighter - and the lighter hearted - for your effort.