OP, I say Samsung EcoGreen for storage. Samsung drives, for the most part, are reliable. Some people say they're a bit more noisy than other drives because of vibration but others say they run cool and silent. I prefer Samsung drives for either storage or an OS drive (if you can't afford a SSD).
I am looking for a storage drive, too, and it is between Samsung EcoGreen drives and the WD Greens. The WDxxEARS series is what I would consider though over WDxxEADS. The only thing to consider though with the newer WD Greens is the new partition format. They have to be aligned for 4K byte sectors or 4096 byte sectors or the drive will perform terribly slow. I mean, big time slow! There's a lot of buyers who didn't realize how crucial it is to have these drives partitioned properly. There are not many methods yet to do that and if you use XP, you need to use a utility on the WD support site or if you use Windows 7, the OS already does it properly. XP doesn't. There's another issue with the partitioning in Linux but that's another story and if you don't use Linux, it won't apply to you. Samsung F2 EcoGreen drives are the old style aka legacy drives that can be used as before.
If you want to try the new technology, try the WD. Most future drives will probably have the same format. Hopefully, there will be better ways to partition them by then. I think it might be good to try the 'new way' but I read a lot of issues with them and Samsung drives get good reviews generally. Maybe go for the best price per GB? Also, I read that is best to go with either 1TB or 1.5TB drives because there's less moving parts and some say drives =/> (equal or greater to) 1TB are a crapshoot. It's all on chance of getting a good one. Apparently, the QC isn't the best regardless of brand. I think it might be good going for either 1TB or 1.5TB since it's either 2 platters or 3 as 2TB is FOUR. Anyway, it's just an idea others have presented but imho, it's not a bad argument.
Hope that helps give some ideas.