Genes vs. Mountains
One potential argument against open access (or to electronic journals in general) is that many copies of a dead-tree journal will be printed but there might be only one version on the Web. I disagree. There's no reason why there can't be many mirrors for an electronic journal. Even if one computer crashes or one CD disintegrates, the journal will have been copied to many other systems.
You can think of the durability of paper journals as analogous to the durability of mountains. It takes time for a collection of atoms to fall apart. Similarly, the durability of electronic journals is analogous to the durability of genes. They're renedered immortal by having copies made.
There are collections of genes billions of years old. Mountains of the same age have been worn down to stubs.