Pro workouts is a big topic. Someone like Nalbandian hits the beaches, booze and babes.

Rafa is probably hitting the weights and cycling.
You should tailor your training to the time of year and the training cycle you are in. It's not simply a cookie cutter approach, which is why the pros hire a trainer.
If you are a weekend warrior and are short on endurance, I'd suggest the following:
1. Lose fat, i.e. get your diet right;
2. Start a 10-12 week training cycle of distance runs or distance cycling. If you are fairly fit, do some 2-5 mile runs 3 days per week, and about week 4 start with some interval work, such as 4 x 200 meter sprints with a one minute rest in between. Continue the intervals after the base building period and raise them to twice per week. Recent research indicates that hard intervals raise your VO2max, and your endurance. It's a somewhat paradoxical effect.
3. Lift weights.
4. Get plenty of rest.
-Robert