Best software? CGMiner is by far the most popular.
Best Pool? That depends. I'd check
Here to find a few pools that you would trust. Bitminter is a very good one. Ozcoin and Slush are also my favorites. BTCGuild and 50BTC are also big for a reason: they're pretty decent as well. I think everyone should choose at least 2-3 pools, rather than just 1.