Oh, eek. I have two weeks holiday left this year and I'm stuck on where to go. I have several options but none are really grabbing me as yet. I've got either early November or late November/December as options right now.

Excluding the odd week or two here and there pottering around Europe, the last few trips I've done were to Australia, Sri Lanka and Thailand, and the places I loved on those trips were Far North Queensland, Ella & Kandy, Chiang Mai and Sukhothai. So mountains, jungles, quiet backwaters, are my sort of thing. Lazing around on the beach isn't, I'd rather hike in the hills and look at the coastline than waste a day sitting on it.

So far I've thought of Central America (Costa Rica/Panama), Vietnam or Cambodia, or do something a bit closer and either Morocco or Israel/Jordan.

Central America - I'm a single girl in my mid 30s, and I just don't know enough about this area to know if I'll be comfortable to wander around on my own; I usually travel independantly on public transport rather than go with any organised tours.
Vietnam/Cambodia - I feel I've done enough of SE Asia for the time being. I'm sure I'll love to go to either place but maybe in a year or two.
Morocco or Israel/Jordan - same issues as central america but I'll probably join a tour. I'm also not too sure if they'll be warm enough. Heading off in december, I'm after escaping the british gloom and seeking somewhere decently hot.

I guess what I really want to know is what central america is like, but some inspiration for ideas of places I might not have thought about would be great too!

I have few suggestions and I have been to all.
If you want to do Central America go to Costa Rica fly into San Jose rent a one way car to Liberia but before returning the car stop and spend night at Manuel Antonio and arenal volcano. Also after returning car you can go to Nicaragua but for single lady I don't know if it is too safe.
Best way to use your 2 weeks will be Vietnam and Cambodia. I did 10 day package tour from local tour company and you visit Hanoi Halong bay hue ann Saigon then take a river cruise in nmeekong delta to Cambodia arrive phnom peh and go visit Angkor watt. The fly to kula lumpur and Singapore and your 15 days will be over. The 10 day package tour was $900 per person including hotel site seeing guide car and transportation.

I'd head to Chile. It is probably the safest place in the Americas after Canada and parts of the USA. Weather should be generally nice, the days are already long, you are very unlikely to have any rain (except occasionally in the South), there are a myriad of climates and terrain (each beautiful in its own way), renting a car and driving is safe and relatively easy.

Israel can already be quite cold in late Nov/early Dec.

I also second Chile. The terrain and geography is varied. Desert, beach, Patagonia, nice smaller cities like valparaiso. And Santiago is one of my favorite cities.
It is very affordable and very safe.
From my own experience as a man in morocco I would not go there as a single western woman. It is just too much to handle.
I know people will say it is perfectly safe. And it can be. It can also feel very intimidating and unsafe especially if you are on your own. And it isn't warm in December.
Chile is very warm in December. I would splurge and go to Easter island which is simply stunning.

Austria, skiing. Just pick your weeks with a spot of care, and you'll have the mountains almost to yourself. My personal recommendation would be Ischgl, which is fairly high and therefore almost certain to have excellent snow conditions.

How about South Africa? Just spent a week for work in Cape Town and a full day doing some sightseeing with a friend who lives here.

You could easily spend a week in the Cape area in December, seeing the sights, relaxing and partying (should that be your thing) safely. Rent a car and enjoy the coast and then fly to Jo'burg and drive to the Kruger Park for your safari fix.

What's the budget?

Thanks for the suggestions, I had written off Chile as being a bit too far but I think it might be possible.
Budget is around �1500 including flights, so renting a car is out really. I also find it's a little bit uninteresting - I usually prefer to drop the pace a little and use a bus or a train to get around.