The Pioneer plaques carry some information but most informations are about humans' shape/body and how to find us, they aren't actually source of that much knowledge because the next intelligente specie will find them on hearth (so location info are useless) and humans are already extinct. Moreover they are not designed to last on hearth but in space. Aluminium/gold is a quite good material but the shape and thickness are not optimal except for the weight (wich is really important only if you have to launch them into space).
I totally agree with Valerio Pastore's answer, beside the fact that you can pretty much place the capsule wherever you want since after a Chicxulub-scale cataclism and after millions of years you can't really know which place will be fine. On a second thought, since the capsule is designed to last millions of years but it doesn't mean that the next specie arrive after millions of years (maybe they will arrive after only a thousand years, who knows), a safe place now is a better choice. Mas que nada...
Our languages would have been forgotten, but people that study how to create messages that should be understandable for ages (100K year) already exist, their goal is to warn people about radioactive scories storages: Documentary film.
Contrary to the pioneer plates or the Voyager golden record we don't have to care about the weight, therefore some more space is available. Knowledge is not well defined and i'm not sure about what you really want to preserve.
Do you want to preserve our history or our science?
If you want to preserve history you could create the new rosetta stone but i guess that after such a cataclism history as we know it is gone, in the best case scenario it will be possible to find some kind of especially rare "fossils" (compared to our fossils) but certainly nothing comparable to our museums or the pyramids or the coliseum (thousands of years are quite different from millions of years).
If space/weight is not an issue then history should be recorded, otherwise i'd go with science. Languages are gone but some huge science milestones could be engraved as images. For instance: periodic table, atom structure, Darwin evolution theory, the wheel (please note that's not obvious, some evolved civilizations didn't develop wheels), crop rotation, our solar system (the new specie could still be hearth native as us), metal casting, Archimede's and Leonardo's designs, Pitagora's theorem, classical mechanics...
This list could be very long and it will be much more useful since the physics laws won't change in millions of years. :)