First thing that comes to mind that can handle both actual diving and your price point in an automatic is the Orient Triton. It's JIS certified (among many things, this also means that the bracelet isn't junk, which is good if you're used to buying Seikos), comes with sapphire, applied indices, 4 o'clock crown, pretty good lume, and the same in-house movement used in their $2,000 pro saturation diver. Long Island has them for $399, last I checked. I had the black one for a while, but sold it (too big for me - I'm 6.5", so I don't like to stray above 40mm).
The Ray II is good, but if you've had a Triton, you'll realize they're not all that great.
If you can find a Seiko MM300, you can't go wrong. Very nice. Might be a bit above your price point, but not by much.
If you're willing to wait, the SBDC063 will probably come down in price once it has fully penetrated the market (released last year).
Citizen Pro Master Sea is a good lineup. Not many automatics, but there are some. If they made a few more models at or below 40mm I would own one.
If you're open to quartz (which gets a bad rap, but for an active/sport/diver watch, sort of a no-brainer), then the options in your price point truly open up. I had the SNE435P (special PADI) edition for over a year and not only was it a looker, but near bullet-proof, and you can actually dive in it. Solar powered too, so no need to crack the case open for like 14 years. Could retain power cell life if left in the dark for ten whole months. In addition, Citizen's quartz movements are the world leader outside of maybe Casio (for sports watches).
If you're a skinny dude, and you like a snug fit, you might find yourself going way above your price point for a properly fitting dive watch. In fact, after wearing divers about half the time since 1981, I recently gave them up completely. They just don't fit me, and there are sporty options out there that do. So keep that in mind. And it wasn't until I put on a watch that fit my wrist so well that it looked like it was virtually poured onto my wrist did I leave the diver category altogether. I sold all my divers (and chronos, since they are nearly always > 40mm too), and focus now only on watches that fit well, and I'm having a lot of fun. So, for "sporty" endeavors, I have field watches, and proper "sports" watches.