I'm suppose to post one normal message before I can post an advanced one so, ya, here it is.
FYI, I have only recently discovered this forum.
I'm not new to the Arduino world, I've made some (advanced) projects before.
Lastly, I've known and used Arduinos for a little over a year now and currently have the Duemilanove and UNO along with a handful of shields.
Well, leds are cheap enough they're easily replaceable after the Magic Smoke is released
But I think I read somewhere that skipping on the resistor can make a led draw too much current and break the Arduino (which is arguably cheap enough to replace too, compared to similar options, not that I'd want to either way)
The main reason you really need to use resistors is of course to support "The Resistance". Those courageous Resistors are out there, giving their all, for you. I saw all about it in a film, black and white- must have been carbon.
I can skip over the you-must-use-current-limiting-series-resistors-with-your-LEDs speech
Do you know what I discovered recently? If you plug some LEDs into a USB port without using a current limiting series resistor on this laptop it pops up a message to tell you that something's using too much power