See main bathymetry page for descriptions of the dataset and where to get them.
ETOPO1 (1-arc-minute) is a noisy, but free, global dataset. ETOPO2 (2-arc-minute) is an older version of ETOPO1. GEBCO (1-arc-minute) is "public" (but actually expensive and non-redistributable?). Note how the data is smooth and well-behaved, but misses features which the lower-resolution ETOPO2 captured. Accurate local bathymetry data for visual comparison, showing the details that the global datasets miss.