This is completely dependent on which exchange you're using. Personally I've found that using CampBX or MtGox with Dwolla transfers has worked the best and is the cheapest ($0.25) for me.

I like Burnside's pool (http://ltc.kattare.com/) because it is PPLNS and has worked well for me. I have read several comments on different boards stating that some people experience high-stales on this pool but I haven't experienced that personally.

Try out a couple and see what suites you!

https://github.com/litecoin-project/litecoin/wiki/Comparison-of-mining-pools