depends on colour mate, I have a black car and like to use poor boys black hole as it is designed for darker cars, and doesnt show up all of the stone chips. It is also very very easy to apply and buff off. Price is good to.

Remember, after polishing, you should be waxing or using a sealant to protect the paint as the polish is cleaning, the wax/sealant is protecting.

detailersworld is a good site to nose around to see what people use, and the results.

Last weekend I did a good clean on mine

rinsed
snow foamed (not essential)
rinsed,
shampood with a mit (less likely to cause swirls)
used tar spot remover to get rid of any nasties
claybarred the car to remove ground in shite - essential
rinsed and patted dry
polished
waxed

Will now be able to wash and wax for a few months till i do it all again.