What I thought when I said
Would using the 12v adapter with a 7805 to power the TLC's cause more glitching, since i'd also be powering the led's with it
was that the leds wil be going on and off a lot, so i thought that might interfere with other circuits running from the same 12v source.. or won't that be a problem?
That's where decoupling capacitors can help.
By the way, would, theoretically, adding 1000 capacitors to a power source, change anything about the output?
Adding 1000 capacitors doesn't matter. What matters is how much capacitance you have added (or the value of each of those 1000).
You need to strike a balance between having enough and not having too much. If you have too much, there will be a large amount of in-rush current when your circuit turns on, as all of the capacitance is charged. (Too much has a lot of "depends" in it. However, thousands of microfarads is probably a good line to watch.)
A 0.1uF cap near each IC's VCC is helpful to smooth out high frequency demands. Sometimes, it may be necessary to put something larger in parallel, like a 1.0uF. FYI, Even if you have 20 of these caps in your design, that's still less than half the capacitance as the bulk decoupling caps on the Arduino board itself.