There have been many debates on this forum about this subject. I suppose it depends very much on what you are planning to do and where you are:
1) If you do mostly w/e sailing out of Poole with the occasional week or two cruising in this corner of the world, then a wind generator will be very useful (we have a Rutland 913 and it is marvellous)
2) If you plan long distance cruising with long transatlantic stretches pushed by the trades, I suppose a water trailed generator and solar panels may be advisable.
3) If you are going to bake in the Med, then solar panels are probably your best choice.
Note 2) and 3) are not drawn from personal experience . This month, in one of the sailing mags, I saw an article comparing combi generators (water/wind). It sounds like a good idea but the feeling I get is that they are quite complicated to deploy and probably also more liable to go wrong... just my prejudice here, though.