If you think you will be doing equal road and off-road cycling then your best option is to go for mountain bikes. But if you plan on mostly trending the roads and going off-road only rarely then I would recommend settling for  simple road bikes. I own a road bike and take it off-road once in a while without much riding problems. But they can get uncomfortable for larger trials. As for the size, there are no hard and fast rules. Best way is to check the bike out for yourself in the shop.

As for hybrid bikes I would personally not recommend them. Hybrids make very uncomfortable rides. I don't know if it's just me. Another issue with hybrids as you already mentioned is the price range. They are too expensive for the benefits they offer. So why waste money on them when you can get great bikes at very affordable rates?