looked at doing this last year and it was sooooo expensive. the cheaper deals seem to be in the days before the holidays or in January. anytime over the Christmas/New year from around 23rd to the 2nd was pricey. it would be a good idea to narrow it down to what you want - skiing or sunshine and then start looking at prices now so nearer the time you have something to compare with. cruises can do some great deals but they go really quickly and you have to be lucky to get one. how many of you? what are looking for snow or sun?
if you want proper sun/mid 20's temp then you are looking at Florida, Caribbean etc near to the equator basically and a fairly long flight. South Africa? have a look on accuweather website for temps of the various places that you are thinking of. Europe will be warmer but certainly not sun if you want it beach weather. start looking at flight/package costs now and if you can fly at odd times then you might pick up something. make a list of a few holidays and make a daily check. cruise any good?