I always used turnips until about 3 years ago. Upsides of using a pumpkin is it's easier and quicker to carve and it's larger for cutting into. Definite downside is the flesh isn't worth the bother of using (I did try the first year but I've been told it's the wrong kind of pumpkin for cooking with) whereas turnip is so tasty in stews etc.

I like the skull effect you achieved, very traditional. We Celts should stick to the ancient practice of displaying skulls with candles in, don't you think? Haha!