Original poster again here. I no longer own the Sunfire, but it is still in the immediate family, and going strong - although it doesn't see the amount of use as when I owned it. I believe it's currently only around 265,000km.
During the past 2 years, it received new wheel bearings on the front (got rather noisy - common issue), and we did the brakes at the same time. The ABS light's been on for about a year now - but hasn't been looked into yet. Everything else still works - just no ABS. It still even looks very good - inside and out. It's nice to see it still being maintained well.
As for the last commenter's question - the fuel pumps are a fairly common issue it seems in these cars - especially if you like to drive on fumes a lot. They seem to run hot when not fully submerged in fuel - or at least that's what I've been told. I always tried to keep it above 1/4 tank, and never had an issue.
The car does have a theftlock feature with the ignition (GM immobilizer) - but I never had it fail to know the symptoms. If you have another key - try it and see if it makes any difference. The keys aren't "chipped" - but a worn one may have a negative impact on the system.
When you turn the ignition "ON" - you should hear the fuel pump run for about 1 second and then stop again. If this is happening, then the pump is likely fine. If not, I'd try swapping the fuel pump relay for another (under hood fuse box) - I believe the fuel pump and fan relays are the same. Still no go? Have someone turn the ignition to "on" while you keep one finger on top of the relay. You should feel it "click". If it does, then the problem is likely the fuel pump or wiring. If not, there probably isn't an easy quick answer without more information. Hope this helps at least somewhat.
I did end up buying a 2009 Vibe shortly after my last update. When GM's future was in question - I knew if I waited my discounts were likely to disappear, as well as the availability of the car. Turns out I guessed right - as shortly afterwards the end of Pontiac was announced. It would cost me about $5k more to purchase a Toyota Matrix instead. I can't see myself ever investing that much into a depreciating asset though - so I'm glad I got what I did. I'm mostly enjoying it so far - but I'll write about that in a separate review. I had seriously considered a VW TDI as someone else recommended - but I've never owned one before to be comfortable buying used - and to get what I'd like brand new was not affordable for me. Close to $10k more than what I've got into the Vibe.