Lots of people swear by bleach, but if you use it you don't have to use very much at all and you have to rinse, rinse, rinse.
StarSan and Iodophor are much more fail-safe I think. If you use them properly they are both very effective and you don't have to rinse.
One last comment. Are you new to homebrewing? If so, you may need to just give your brews some time. I think most of us here have learned the hard way (by drinking up most of a batch of beer only to find when there were six bottles left that it was suddenly GOOD!) that it tends to get much better with age. Even though the books all say it is carbonized and drinkable in 2 weeks, it is normally nowhere near its peak flavor at that point.