From time to time, xkcd has quite nice and scientific illustrations; recently, for example, a to-scale and non-logarithmic represenation of lake, ocean, and borehole depths:
Interesting, that some ships sank in waters less deep than they were long…
The Mariana trench doesn't look very “trenchily” steep without vertical exaggeration (i.e. same scale for lengths and depths).
And I hadn't known that the Deepwater Horizon borehole was that deep – almost as deep as the Russian deep borehole on the Kola peninsula.
And something else about the oceans: NASA shows some impressive animations, called Perpetual Ocean, about the ocean currents that have been numerically modelled on the basis of satellite and in-situ measurements. On that page, there are some links with details on several regions, e.g. the Mediterranean or the Gulf Stream. Thanks to Christoph Larssen (ErklärFix).