i always stay in Perranporth, as it has a massive nice beach, is kind of central, has a bar on the beach that serves excellent food, has all the shops and ice cream shops you need, and its easy to get anywhere from there.
it also is surrounded by holiday sites and is just down the road from Newquay (if you want to go where all the crowds are)

cant add much to the lists above really, but can say that its really nice down there. and i need to go back soon.

Lanyon Quoit is a must.

oh and there are so many sites to visit that i still havent been to them all and i have been going down to Cornwall for the past 8 years, sometimes twice a year. i normally fit in 2 days of stones in the week we are down. we do tend to visit some everytime though as they are brilliant. like Men-an-tol.... sorry im rambling now. i love cornwall.