Buy the 60GB version now for $500. You can upgrade the HDD to 160GB for under $150 and you get the full hardware backwards compatability (versus the limited software emulation in the 80GB version, similar to XBox 360's backwards compatability). So for $50 more than the 80GB version, you get twice the HDD space and better hardware.

Also, buy before 9/30 and you get a mail-in for 5 free Blu-ray movies. They are from a decent selection including Underworld Evolution, Transporter 2, Corpse Bride, etc. I bought mine this week using a Fry's ad that threw in Casino Royale and Hellboy Blu-ray DVD instantly for free for 7 total free HD movies! (No Fry's in my area, but Best Buy matched the ad!)