Some of the proposals for super-long term storage are indeed pretty silly, but the idea itself has some merit. We simply can't guarantee that we'll be around as a civilization long enough to make sure an easily accessible stash of nuke toxins will be safe for future generations. Fortunately, the loonier science fiction scenarios could easily be replaced by something more practical.

There are many abandoned mines around which fit the criteria of geologic stability, no ground water, and predictable structural integrity foir the indefinite future. Salt mines, in particular, have the added advantage of high thermal conductivity to dissipate heat from the vitrified wastes. In the event we forget where these caches are, or are incapable of maintaining and guarding them, they will not be likely to bother any of our descendents or even be locatable or accessible to them.

The important factor is that as long as we know where they are and have the technology to revisit them, we'll always have the fall-back position of changing our minds. We don't really know how stable those glass blocks will be after being subjected to heat and ionizing radiation for hundreds, or thousands of years. Some schemes, like inserting them into tectonic subduction zones, might work, but are non-reversible; not a good idea, in my opinion.

The greatest obstacle to waste disposal is not technical, it's political. The public wants no part of them, especially not where they live. But that's a moot point. The waste is already here, and it's not going to go away. The important point is to replace the thousands of tons of old, deteriorating fuel elements we have lying around with a few tons of concentrated, stable glass blocks which can be safely moved around anywhere we like until we find a place to put them...forever.