The bathymetry in Google Earth (the topography of the ocean floor) is something that has been gradually improving for years. Not counting the 3D ocean released in 2009, the bathymetry imagery has been improved a few times as well including an upgrade in 2009, and then again in 2012.
While the Google Earth bathymetry is quite solid, there are other sources that do an excellent job of presenting it as well. One of the best is GEBCO (General Bathymetric Chart of the Oceans), who just released the third version of their map in a variety of formats.
They offer massive PDF and GeoTIFF downloads of the map on their world map page, but they also offer it in a few formats that are preferable to people like us — Google Maps and a great downloadable KML file.
For more check out the full details and information on their website.