Chains and Sprockets

[BEAR]

Did a major clean of the chain, and when nice and clean, noticed it was very noisy on the drive sprocket. Thought it would quieten down with lube so applied the magic spray, but it is still noisy. I guess it's the original and maybe at 40,000 km it's due for replacement. So, if I'm doing that, I'll junk the chain as well.
Question, since my bike is probably going to do drags for most of it's Kms this coming year, what sprocket and what chain is recommended? <i></i>