You already know the answer don't you. It depends on what you are photographing and what you want to say about your subject. Why not try photographing your sitters with a wide angle lens and light them from below, like the footlights in a theatre? This grotesque and dramatic style will get peoples attention. Can you imagine a portrait of Gordon Brown or someone similar using this style. My subject choice reveals a lot about my thoughts of the last Prime Minister! Robert De Niro could be a great subject for this kind of treatment. It is important to express your feelings about your sitter and not just take a flattering portrait. You can always do a couple of variations to make sure that you have that 'Knockout' portrait that is going to get you noticed.
In the pdf below you will see outlined the key factors that will enable you to make the right choice for your photographs and gives a break down of the important things to know about lenses. There is much more that could be added however it can all get quite technical and a bit dull.
What are 'Ghost Signs?'
There is a great new program on BBC 1 on Sunday nights (available on iplayer) which provides many exciting ideas for photographers. One that caught my attention was the natural forest on Dartmoor national park.It is the last remaining natural forest and has a wonderful atmosphere about it. It is like something out of a fairy tale by The Brothers Grimm.