Workout Table

Below is a table that will help you sort out what different machines or weights can help you with.1*= Does it, but not too effectively, 5*=Accomplishes it to the fullest.

(Part Five)
Dumbbells-(As you can see I saved the best for the last and my personal favorite).  

Advantages-Dumbbells give the best of all worlds, isolation, strength and muscle growth, independence, variation, less of sticking point 
than bbell.  Difficulty of dumbbells is harder due to controlling the weight.  Lifting 150lb dbbells over your head takes a lot of work and 
makes the whole body work to control the weight, especially the shoulders and abs (I like to say a workout inside of a workout).  
To make dumbbells more versatile for home is to have an adjustable set.  This allows for many variations for a home gym.  
There are hundreds of dumbbell exercises, sometimes I will do an entire workout of dumbbells, due to the advantages they have 
over the other machines.

Disadvantages- There aren't many, but they do have some and one that plagued me last year was weight.  The 150lb dbbells were 
becoming too light for me for most exercises (bench, rows, shrugs), pre-made dumbbells can lack versatility and can become costly 
to buy your own set, stick with adjustable weights for at home.  Luckily some guys machined up some 170s and 180s to great 
enhance my workouts.

(Part Four)
Barbell

Advantages-When you think of barbell, you think power! Most of the main strength or powerlifting exercises are done with the barbell (bench, deadlift, squat, clean, 
jerk, overheadpress) Provides basic exercises for base development in strength and muscle building.  Most exercise are not very hard to do, simple compound movements.

Disadvantages-Not a whole lot of independence for individual arms, if one arm is weaker than the other, the power arm will always take over, not great for isolating, 
toning or cutting up.  Tension is usually only in sticking point not through the whole movement, easier to cheat up reps(can be good and bad), form is usually 
not very good.

(Part Three)
FreeMachine(What are freemachine? These are machine such as Hammer and Cybex that have more freedom, especially single arm movement capabilities.

Advantages-More freedom and variation.  Can be used more effectively for building muscle and strength than regular machines, but at the same time stress excellent 
isolation for toning and cutting up.  Freedom to use individual arms for forced reps at the end instead of of both locked in at the same time all the time.  One of the best 
advantages of these type of machines is that you can load them with regular plates and this allows for optimum resistance with form, which can be extremely effective 
in building a competitive physique, also allowing you to perform to failure with heavy weight and no spotter.

Disadvantages-Very expensive, if your gym has more than five pieces of this type of equipment, be thankful, most of the machines are $3,000 a pop. Not feasible for 
home gyms, unless your extremely wealthy, (but in that case you wouldn't be reading my page, you would be consulting your own personal trainer).  Not a lot of variation,
sometimes you can come up with a different exercise or two other than what you are supposed to do on it, but overall expensive, but effective for one exercise or bodypart.

(Part Two)
Machine

Advantages-Very strict form, no need for a spotter.  Changing weight is fast and easy, can speed up workout if short on time.
Can be great for rehabilitation, toning, or cutting up. Can peform strict form with excellent isolation of single joint 
movements.

Disadvantages-Usually not a good strength or muscle-building format.  Also, typically the weight stacks only go up to 200lbs,
not enough for the serious lifter.  Mostly single-joint exercises, can't do many compound(more than one muscle involved) 
movements.  Not a lot of variety, stuck with the one movement the machine performs.  Also expensive, machines are typically 
not good for home gyms, even the all-in-ones, they are quite bulky and offer limited variety and expandibilty.  

(Part One)
Cable

Advantages-Can do many exercises and has flexiblity for multiple variations.  Great for toning and cutting up for a show.
Easy to use and no need for a spotter, rarely any safety issues.  A lot of independence with single-arm exercises and with 
multiple bars two-arm exercises can be fun and inventive.  Isolation, full-range of movement, and feeling the burn is key to 
cable exercises.  In addition, one of my personal favorites (BBTOW-6.11.02) is do posing exercises with cables.

Disadvantages-This is my personal opinion, but I don't believe many BB or PL would disagree, using cables is not a great way 
build muscle and develop strength.  Most exercises should be finishers or warm-up, but not the bulk of your workout.  Other main
DA include you will only find good cables at a gym, hard to get decent cables at home that can accomodate any kind of weight. 
Even at a good gym most stacks go to 150-200lbs, which sucks.  You can load only so many plates or dumbbells on top of it, 
until something breaks (including toes).