LED Help!!!!!!

I would recommend a string of 74HC595's (there are also dedicated LED drivers). This will remove problems with ghosting. 74HC594's can do a similar job.

Each 74HC595 can control 8 independent LEDs (or strings of LEDs).

3 outputs of your microcontroller can do the whole lot.

120 LEDs (assuming 20mA each) will require just under 2.5A from your power supply.

 

The chip you suggested is not a latch, it's a set of D flipflops. With this you can either create a latch, or a shift register. It's pretty common to use a shift register to load up a series of LEDs, and that's what I thought you were doing. Perhaps you're using these to latch a parallel signal, thus needing 8 parallel bits and n control signals. It's pretty wasteful unless you need really high speed.

You either turn all the LEDs off (using the tristate output) while you load a new set (which may introduce flicker) or you keep them turned on and risk having some ghosting as the bits are shuffled along.

The 595 has a latch so you can load all the bits then change them all in a single operation. You can do this at several MHz, so the entire load operation will take some small fraction of a millisecond.

 

Hmmm, can't see how this can reduce the current. Perhaps if you have a switchmode driver you can, but not with PWM. The same average current is the same average current.