If you can, I suggest getting *2* EHD's. I currently have 2 Western Digitals (a 500GB and a 1TB) and have never had a problem with them. I also have an Iomega (250GB) that is 4 years old and still going strong.
I suggest getting 2 EHD's, because if you put EVERYTHING on the 2TB EHD and no where else, when it goes (and it will go), then you're still screwed. A single EHD not backed up to a second source isn't a real back up method. Just wanted to point that out.
Oh, and just like any hardware, you'll hear horror stories from people who have Western Digital EHD's blow up within a few days or months of use. It's just like the Hp vs Dell vs Mac debate. Find one you like and can afford, and just go for it.