What work out regime gets the best results?

Paired with eating well, is there a "sure fire" way that a certain work out routine will work?
Like..Cardio one day, full body weights other
Or should you alter your weight days as lower body one day, upper another?

What do you all do?

"Ideal" will be largely individual and your current fitness level and your body composition/training related goals will play a huge factor.

The workout regime you'll do every week will get you the best results. It doesn't make sense to tell you "3 days of weights & 3 days of cardio is the best" if you only work out 3 days a week. And people have different body types so they will respond differently to different types of training. If you have a chance to work with a personal trainer, that would be a good place to start. He/she will take the time to get to know you, your background, & what is realistic for you to meet your goals...so defining your goals is what you should do first since your plan will follow that.

ETA: You asked what we all do...I do cardio 5-6 days a week & strength train twice a week. My current goals are to complete a duathlon, a 10-mile & a half marathon by the end of October, so my cardio consists of running/cycling with increasing mileage each week. My strength training routine was developed by a trainer I worked with at my gym who is a triathlete so I felt he was well-qualified to help me meet my goals. The routine consists of exercises that will help me become a better runner, so there's lots of balance, plyo, core, & hip/glute stuff. If my goal was to build/define muscle, my strength routine would be completely different.