@epdon
No disrespect intended - I didn't know you were already an Amiga user. Your question lead me to think you were asking whether Amigas are worth getting. We all know the answer to that :-)
Just to reiterate what cgutjahr said, the Aminet CDs themselves will work just fine on a PAL or NTSC Amiga, but if any of the software on it is specifically written for one video standard or the other you may have a problem with that specific piece of software.