It is really important to choose a broad spectrum sunscreen that protects your skin from both UVA & UVB rays. UVA is responsible for skin "aging", and UVB is what generates a "burn" or redness to the skin, both of which can contribute to skin cancers. It is reported that two in three Australians will be diagnosed with some form of skin cancer by the age of 70.
And remember, the best sunscreen is the one that you feel good about wearing every day. Choose an SPF 50 if possible. For sporting and active days, choose a waterproof sunscreen. Otherwise, it really is a matter of personal choice.