The question often arises, especially from beginners, about what type of routine to use. Your buddy told you to use a full body routine, but the muscle mags suggest a 5-day "bodybuilder" split. You don't want to start off on the wrong foot, but there is so much information out there that sorting through what to do can be difficult.
This is some of my opinion on the subject, and maybe it'll help a few people out.
Full Body Routines:
In my opinion, this is the place for a beginner to start. I have many years of lifting experience, and have pretty much always used some form of bodybuilding split routine. However, if I had it to do over again, I would have begun with a good full-body routine, built around the compound lifts, done 3 times per week. When you are a beginner you don't generally have the muscular strength to work intensely enough, or with enough volume, to require as much recovery time as someone who is stronger or more experienced. If you are a young beginner, on top of that, you have very good recovery abilities due to high hormone levels. So, because you are recovered relatively quickly after each workout, you want to stimulate each muscle group more often to induce strength and growth.
Another reason to start with a full body program is that this gives you the opportunity to learn and practice the basic lifts: squats, deadlifts, bench press, overhead press, barbell rows, etc. Whether your goal is bodybuilding, strength athlete, sports, or just remaining fit, these really ought to form the basis of any routine. No matter what path you choose to "branch out" on later, these core lifts will serve you well.
2-Day Split Routines:
So the next question becomes: when should I think about split routines? In very simple terms, the answer is: when full body routines become too much. Usually, as you get stronger, it becomes very difficult to maintain enough energy to do squats, deadlifts, bench press, etc. all on the same day. You may also find that you want to add in a few isolation exercises to bring up your weak areas, or you may want to begin focusing more on each core lift. Another issue is recovery; as you get stronger, you are able to work out more intensely, and that means longer recovery times. So at that point, it makes sense to "split" things up by only doing a part of your previous full routine on any given day.
A logical place to make your first split is into an Upper / Lower type routine. This will have you doing your upper body work like bench press, rows, overhead pressing on 1 day, and your lower body work like squats on another day. Another way to go would be a "push/pull" type split where you do all your pulling exercises (rows, deads) on one day and your pushing exercises (squats, overhead press, bench) on another day. Exactly how you do it is up to you, but the point is to divide the workload per session. This will give you more time (and volume) per body part, and also give you a bit more recovery before you work that muscle again. Most people will typically cycle through a 2-day split like these twice per week. So instead of every muscle being stimulated 3 times per week with the full body, now it's twice per week with the 2-day split.
3+ Day Splits:
3, 4, 5 (or more!) day splits come in when you again feel the need to divide your workload to match your recovery abilities, or increase the amount of work you want to do on specific muscles or lifts. Generally, these type of splits are mostly bodybuilding related, but even strength athletes may chose to split so they can work on speed lifts one day, strength work another, etc.
At this point (speaking to bodybuilding) many lifters will only hit each muscle group once per week. This has the advantage of letting you really hammer a muscle group with a lot of weight and volume, and then give it plenty of time to recover while you're bringing the pain to the next group. Your full body effort is broken down into segments that are manageable from a workload, energy, and recovery standpoint.
If you are an "experienced" (older) lifter with decreased recovery abilities (we all ain't as young as we used to be), this type of split often is useful for staying healthy due to the increased recovery time per body part. The kids might not think it's important, but your tendons might.
There are so many variations of splits that I won't even attempt to detail all the possibilities. If you follow the advice in this post, by the time you need a multiple day split, you'll know your body, your goals, and have a pretty good idea of what you want to do.
I believe it's a logical notion to start with a full body routine, and begin splitting only when you feel the need to increase your recovery or increase your volume. If you stick with the concept that you're trying to hit a muscle as often as you are able while still recovering adequately, and let that be your guide, you'll do okay.
Hopefully, this gives some food for thought to help you decide what type of routine you should use. Ultimately, however, it's worth saying that you can do fine with any well-designed program even if you begin with a split routine right from the beginning.