bazzer: I'd honestly just go for the 320GB now if I knew all this beforehand.+1
I've now sold PlayTV and purchased another PVR. I'm looking at buying a 320Gb drive to put in the PS3 so I can use the 500GB in my PS3 for the new PVR. One day down the line I'll get another playTV, and it should work then.
We can't complain about a product that's not even supported here, but that said, it is released officially in Auz and people there are experiencing problems with larger HDD's. You'd think Sony would be onto it, but it's taken years for them to get onto some updates. They left France with no reception for a long time after France adopted our style freeview. Lately they've only seemed to release big updates, whereas a lot of us would prefer smaller updates that quickly corrected faults like the HDD size issue.
That said, I really do think there is still a chance of this being signal related and Sony has offered no on screen info page to describe signal quality. It's been well documented that PlayTV requires a stronger signal than most other set top boxes that work where playTV does not. I don't know why that means I could watch TV fine, but would have big problems when I recorded anything though. I stand by the concept that if you can watch live TV fine on PlayTV then you have a good enough signal. If it breaks up 5 mins into recording and watching at the same time, then you have a HDD problem.