They are selling for $300 and up, I'll wait until they are a commodity and come down to $75 before I purchase one.
Better wait til they have millions of spanking songs to download. If RIAA stopped its stupid lawsuits and saw the cash cow its sitting on, it would tell Apple to please hurry up and c'mon. They're never going to legally put the P2P networks out of business through legal bullying and extortion.
You can get a 4GB (soon to be 5, maybe 6 GB) iPod mini for $250. Rumors say a sub $200 flash player is coming soon.
I think Apple won't ever break the $150 barrier with anything they sell. They do a good job of staying out of low profit margin commodities. (Airport Express - a wireless basestation that hooks into your stereo, may be the sole exception, at $129.)