I love automatic watches whether Swiss or Japanese, but for the money it's hard to beat Seiko's auto dive watches. You might look at the Seiko SXK007/009s they a more classic in style, but the mods are endless for them.
I honestly love the SXK009 more than the Submariner that inspired it. (I can respectfully say the Rolex inspired it, and pretty much all Submariner homages, right?)