StarSan. Easiest to work with. A 32oz bottle lasts me about a year, brewing about 20-25 batches a year. You can reuse it as long as it maintains it's acidity. I have a spray bottle of dilluted StarSan I use for sanatizing pretty much everything, then keep a keg of StarSan solution near the kegorator for cleaning beer lines and fermenters. StarSan is pretty much the standard for homebrewers.