This is going to make some "experts" think I am crazy, but for the vast majority of people I say; "No, do a full body workout !" There are a few reasons I say this;
(I do believe in utilizing split workouts for weight trainers who have been at it for more than a year or two, but I'll get to that in a minute).

This is one of the main reasons I like to do full body workouts, you work out with weights three days a week, (or every other day if your up to it), and get great results, (don't forget your cardio workouts, however). You probably know that you need to give your muscles time to recuperate after a workout, so you can't work a body part two days in a row. If you do try to work a body part too often, then you are bound to become a victim of Over Training, a very real phenomenon that will put an end to your progress and throw a wet blanket on your enthusiasm. With my method, you work out with weights Monday, Wednesday, and Friday, alternating with some sort of cardio on Tuesday, Thursday and Saturday. Then take Sunday off, if you feel so inclined. (any alternating day combinations are fine, I just like that particular schedule). Do two or three sets per body part, Depending on the body part. (See: Sets, Reps and Weight), three days a week.

It may be that you can work out with weights two times a week and get decent results, however I believe that you should perform three workouts a week, (or every other day), to get maximum benefits. Research has indicated that two workouts a week may be almost as effective, but is almost really good enough?.

Don't misunderstand me. Split training is a good method. People who have been training for more than a year or two, and want to push it a little further will need to split their workouts to continue to force adaptation. Again, for the vast majority of people, full body workouts make sense, but if you want to focus on seriously building more, larger muscles, it takes a little more intense training, and more rest in between working a particular muscle group. This is where split-training comes in. You do more sets for a particular muscle in the same workout, but you only work selected muscles, saving the rest of your body for another day. More work and longer rest, along with proper nutrition, can stimulate more muscle growth. You can split up the body parts in any number of ways. Some people like to split "push" and "pull" muscles, quads, chest, triceps and calves being "push" muscles, and hamstrings, back, biceps and forearms being "pull" muscles. (you have to decide where abs and shoulders fit in). Other people split upper and lower body. I think you should utilize split training only once you have achieved a fairly high level of muscular fitness, beginners should definitely use full body workouts. Even for those who do feel it's time to start splitting their training, keep in mind that mixing up your workouts keeps your body in an adapting mode. That being said, I believe that you should routinely come back to full body workouts and circuit training.

You must change your routine periodically to continue to stimulate your muscles into adaptation. If you pound out the same workout endlessly, your muscles become accustomed to it, and do not react as positively anymore. By the same token, you want to stick with a particular workout long enough for it to be effective. So every 2 weeks or so, change those exercises, order of exercises, and even throw in a circuit training cycle once in a while. (See: Sets, Reps and Weight). My Printable Workout Logs provide for a different workout every two weeks to make it easy on you. You also might think about altering your set and rep structure every so often, (See: Periodization and Intensity).

As I said above, your body needs time to recuperate after an effective workout. 48 hours between workouts for any given muscle is a good guideline, but you may find that you need more time to recuperate. This is fine, and should not worry you. I do not advocate being lazy, but if your muscles are still sore from a previous workout, you would be well advised to wait another day before hitting the weights. (See: Over Training) Your body also needs a break from long term stress applied over a period of time, (See: Periodization and Intensity).