Great point. Many years ago, I grew to dislike Becks because of the metallic taste. I always got in in the local bar, and always drank from the bottle. I'll have to try it again decanted.
That said, I am having a problem with a beer I just finished. After 3 weeks in the keg, it was great. Touch of sweet, great hops aroma (cascade) and flavor (kent iirc). At 4 weeks, the aroma has dropped of considerably, and it has a distinct metallic bite. It's still a good beer, but it reminds me strongly of that Becks bite.