I made the switch from a fat-backed TV to a wider, slimmer plasma and soon followed with an upgrade for my amp and speakers - the plasma looked ridiculous on my old entertainment unit and the new amp didn't fit.
To give you an idea of how big the new unit is, the TV in the picture is 50 inches. It hung over the ends of my old unit (as seen in the coffee table Instructable).
So it was time to make a new entertainment unit. This would be my first serious attempt at wood work. The most I had done before this was to repair or update existing furniture.
It had to fit my new centre speaker, contain storage and ventilation for my amp and I wanted the cords to be (relatively) easy to get to.
With nephews and nieces running around, I also wanted to protect the gear from prying, poky fingers.
After a few hours of thinking and several sketches, I came up with something along the lines of the pictures below - which of course morphed as I worked on it.
Because your design should match your individual needs. I haven't included exact measurements for every little component of the unit I made.
The point is really to illustrate that you can and should make a custom unit to suit your gear and maybe save you some money that you might have otherwise spent on one of those laminated modular units.
You should end up with a piece of kit that will last you for many years to come - and what's more, if you ever dent/scratch/damage it, you will be able to repair it!
I hope it will serve as inspiration for your work and I look forward to seeing your results!
PS> I am Australian. We use metric measurements and spell words like centre, metre and generally use "ise" instead of "ize". So you will see a bit of that.
Here's a site that might help you ye-olde-worlder's measure stuff *cheeky grin*
Step 1: Planning
Do you want it to take up an entire wall?
Do you want it to be minimalist and small?
What do you need to fit in it?
How much of the room will it take up?
Will it fit through doors?
Can you move/carry it?
How will you run your cables and are you going to keep them hidden?
Is airflow important to you and the life of your AV gear?
Do you need extra drawers?
A secret compartment? >:)
What about security? From thieves or accidental damage?
Write a list of items you need to put on shelves and sketch out some designs if it will help you visualize where you want to store each piece of equipment.
General thoughts about dimensions and things to consider..
Okay, so look at your AV gear and work out how deep the entertainment unit needs to be to accommodate it.
Measure your equipment - include the knobs at the front (so the door won't close on them!) and don't forget the cables at the back. Some of them can be stiff, inflexible and stand out a fair way..
So you'll need to include enough room that they will all fit without rubbing/bending/breaking plugs.
Don't forget to Include the depth of the wood used for the front doors plus their knobs, plus closing clearance so it doesn't hit your gear. Room for cabling at the back and some way of keeping it off the ground.
Remember the overhang from the top ledge, the thickness of your back panel (if you plan to have one) and you may want to factor in skirting boards if you want the unit to sit flush with the wall.
You probably won't want your unit narrower than your TV , as it will look too small and poorly designed (conversely it will make your TV look bigger !).
If you don't need to accommodate a centre speaker, you can make the unit the same width as your TV or a bit wider.
Remember the width of your gear. Give it a little room to breathe and allow for air flow. If you want your gear to slide in/out from the front, remember to make the doors wide enough for it.
Generally, lower units are more contemporary, but it depends on what look you are going for and what you need to fit in.
How high is your couch and coffee table? If you watch a lot of TV laying down, you may want to make the unit slightly higher so that drinks on the table won't block your view.
How many shelves do you want/need to hold all your gear? Are you going to buy a new Xbox/PS3 next month?
Again, leave some room for airflow.
Lastly.. consider what I call trimming (not sure what it is actually called). But I refer to routed/curved/fancy edging that you might dress the edges with to change this thing from a simple box to a piece of furniture.
The structure of your joins and the height of your trimming may be a factor in the height.
My overall measurements
187cm long (top surface that has some overhang)
62cm deep (top surface that has overhang at the front)