Do I need an Amp for the ATH-M50's for everyday use with my ipod?

You will not need an amp for your ATH-M50's playing via iPod.  Keep in mind that if you are using an iPod nano you may have to reset the volume limit to get the oomph you want, but I tested my M50's recently with my nano and they work just fine.  In fact I was able to really crank up the volume to eardrum damaging levels.

If you want to save some money the Creative Aurvana Live! Headphones compete nicely with the M50's and are about $30 less.  Both headphones are excellent headphones and improve with better source material and amping, but you do not need an amp to enjoy either set of headphones.

Best of luck.

I found that the M50 sound a lot less dark with an amp. Mids and highs really came through, it wasn't as muddy as without an amp.

I did only test for 10minutes with a friend's M50. But he noticed the difference as well. I was using the mini3-amp.

No, you don't NEED it.  It can improve things slightly though.

You need something to get the music from the digital file in your device to analogue signal that drives your headphone.  The device might have a low distortion internal amp.. or not, since it is most likely a low voltage circuit constrained for battery life. You are fortunate if the device has line output suitable for driving an external amp.  With the amp, you can compare the sound of your device to your in-home system.  If you notice a difference, the decision may come down to how you experience your portable music.  Are you listening to it or just playing it for background? Is it a live orchestra or studio production?