LEDs are cool after the 1st month you have them. for me, they got really annoying and I had to swap them for non-LED fans.
you just need an off switch for it... I had mine done with an adjustable knob so I can control the brightness. BUT LED are sweet... makes people check your sweet rig out!!
Yeah, I've had the bad luck of 2 failed switches with a setup like that... wasn't worth the hassle...plus, when my friends see my rig they say "Nerd!" more often than "Cool!"
I like minimalist case designs. So fewer components in general is what I aim for. I try to maximize quiet&cooling more than aesthetics, but that's just me: I like my cases to look really bland and boring

And actually, if you go too nuts with LED fans, you have to start thinking about how big the PSU is--current draw is (by nature) larger on an LED fan than a regular fan, and it compounds with more fans. Not by a lot; but if you've skimped on the PSU wattage, it's def a concern.