On the forums there is a tendency for people to upgrade their displays. They may start with incandescent lights and put four strings on a mini tree. Eventually they will want to update their trees with dumb RGB strings, and finally they will put on smart pixels. So why continue to upgrade your display elements, go straight for the smart pixels.
There are many types of pixels that you can buy. A good place to start for your display would be with the bullet type pixels. These are the least expensive and sealed in hard epoxy, so they will survive just about any environment. The bullet pixels come in either a round sealed package as shown or in a square package.
These pixels can also be bought with a bezel to cover the LED as shown below.
Pixels can also be bought on a pixel strip. These can either be in a waterproof jacket or open to the environment. The strips are available in two common pitches 30 and 60 LEDs per meter. These work well for trees, signs and icicles.
The final major type of smart pixel is a LED panel. These can be bought either as indoor or outdoor, with different pitches (3mm per pixel through 20mm per pixel). These require a special controller to drive them, since they are not really smart pixels. These pixels are either ON or OFF and the controller creates the intensity differences for each of the color red, green, blue LED’s. These panels support a standard interface call HUB75. The panels are bought with either a 8:1 or 16:1 scan rate. This basically means that only 1 of 8 or 1 of 16 lines are on at any one time. So the 8:1 panels are brighter than the 16:1. Per pixel, this is the cheapest way to make a sign.