I have also been feeling an itch for a big ol' metallic tote bag recently so I get it.
As to looking dated, it does seem like I've seen/heard more about metallics in the last couple of years than I had in the past. So I understand the concern. But if I had to pull out a crystal ball, I would suspect that metallics will become a "new classic," along the lines of skinny jeans. Analogous to the way skinny jeans are practical for cold/wet weather, metallics strike me as practical in an aesthetic sense -- instant shine and go with everything, a kind of neutral with oomph.
I do like the bags that people have posted that are a bit more muted, I think those might have more staying power. That said, if you are really drawn to the super shiny one I won't argue with you!
Oops, cross posted with Angie!