Buy the 5g. There is no real confirmation on exactly when the 6g will be coming out, and the 5g is worth getting. I'm happy with mine. But it just depends on whether you are willing to spend the money twice.
I heard that 6g is coming out real soon. I also heard it will have widescreen and making it more PMP (portal media player) and have longer battier life. If it's coming less than 5months i can wait.
It isn't confirmed, as Lethal said, but Apple has a way of just revealing things as they're about ready to launch. Depends on your needs really, I've got my iPod mostly for the music. The video part is pretty awesome though. So it comes down to what you want, I like my 5G iPod quite a bit, but if your in it more for the movies and believe the rumors, then you might want to stick it out a few more months.
I think Apple will always have a fairly basic model of something for $300. I'm not even sure if this 'Portable Media Player' Apple is rumored to be developing will be considered an iPod, I doubt it actually. It will just be another branch of portable entertainment for Apple. I would assume at the [bold]lowest[/bold] it cost $500. Apple charges for their products, and knows people will pay for them.
We'll have a much better idea when there is a confirmed picture of what it's going to look like, not that it will matter much by then as there will probably be an announced price at the same time
There is a picture in my shoutbox - Confirmed? No. But A lot of sources suggest it is the genuine article.