i have an older iMac and want to know if anyone thinks it is worth updating or buying a new one?

updating the operating system rarely speed up older computers as newer operating systems have more features and as such rely on the hardware being faster

You don't say what OS that 2008 machine currently has. What you have could well be upgraded to 10.9. Mavericks. Snow Leopard is an excellent OS and the 10.6.8 upgrade (if it's needed) gives you App store too ... and that makes it a very useful computer. But upgrade the memory to 4GB

Okay, Apple no longer formally support it but they still provide security and iTunes updates ... so it isn't actually dead. And more important, any PPC apps that are currently on it are protected ... at least until you go into higher OSs.

I think I would be inclined to get all I can from the existing machine.

I have an 2008 imac but it is really out of date

The computer itself is not out of date if it can run the newest OS and applications.

Go to Apple menu / About This Mac / More Info ...

Look at Hardware Overview on the right. The Model Identifier is there.

That info will tell us what OS it can run .

I'm also using an '08 imac running 10.9.1 and it runs fine. The OS is not impededby the age of the hardware at all. That being said, it does take some time for some tasksto open. I see plenty of beachballs but it's not much of a hindrance. I've maxed the ram and try to keep the HD lean but find it difficult with four users installed. I find myself asking the same question though. I'd love to have the new imac and was just before this costing out a BTO 21" and figuring whether I can afford the payments. (I can't, yet.)

So, really, you can go either way.

But if you can afford it, brand new IS best.

Hope this helps.