I still have the original battery in my 07 Fahrenheit GTI. I cannot believe it has lasted this long (I have about 53k miles on the car, but still, it's 10 years old), but each winter I get slightly worried. This year, with the colder weather, it seems to be struggling more, so I cannot procrastinate any longer. I looked at the original battery and it's a VARTA, which I'd never heard of. I think I will go with the Duralast Gold, from Autozone, after I find a coupon.
EDIT:
Just called my local stealer, to see what I could get one of their batteries for. It's $30 less than the Duralast Gold, has a 3yr replacement warranty, plus 2yrs prorated. Seems like this is my better bet, so I plan to go that route. My current (OEM) battery has been a champ for 10 years, hoping for similar quality with the replacement.