I still think your the computer you are describing is overkill. Like I said before, I am cheap and always try to go with the bare minimum possible. You will like this machine, it just isn't how I personally would spend my money.
quad-core means it is like having 4 processors but actually you only have one. It used to be very easy compare processors. You just looked at the numbers. The numbers are almost meaningless now without looking at a table.
32bit Vista and I think all 32bit OS's can not recognize more than 3.5 GB of ram. Motherboards also have a limit of how much they can recognize. 12GB is ALOT. I do not know the limit of Windows 7 64bit or of your motherboard but before getting 12GB make sure they can support them. Just because HP is willing to sell it to you does not mean it will work.
My laptop has 3GB of RAM and has never given me a problem. I have never used more than 3.5. You can get away with much less.
I would say do not get the extra memory at all but Seahawk is right $160 for 4GB is very cheap. It is possible to buy the extra 4 or 8 later when the prices have gone down even more and add them yourself. They just snap in. Very easy.
Lightscribe means that your DVD burner can print a label on special DVDs. The label is just plain text, no fancy fonts or graphics. The special DVDs are more expensive. Save the money and get a regular DVD burner and a permanent marker. And use a thumb drive instead of a DVD burner when you can.
Get a good anti-virus. I use
Antivirus Software, Anti-Spyware and Internet Security | F-Secure It is very good. Better than norton and avg.
I said this before, probably any problem you have on your old computer can be fixed by cleaning the fan and reinstalling Windows.
Windows 7 is better than Vista and XP. Especially on a computer as fast as the one you are considering.
64Bit OS are the future but in the present they can sometimes be hard to use. Not all software is 100% compatible yet.