I didn't use anything on DS until his bum went a bit red. Zinc & Castor oil cream is excellent for sore bums and easy on the wallet too!
Welcome to the world of WAY too much choice! I bought a Jurlique baby care pack (exxy, but lasted a long time) for when he was very little.

Anyway, if you can't decide - check out the bounty bags, you should get one in hospital, there are samples galore.