If you like the Pioneers, go with which one you like. That's what I did.
I bought the 05. I liked the slick front with the touch capacitance buttons, the two year warranty, and superior analog section. If you are using HDMI, the two will perform the same. If you use the analog, the 05 will outperform the 51. I use the analog for CD playback, so it's a small advantage.
If you shop around, you can get a deal on the 05 that makes it a little more attractive.
If you are just looking for a good BD player, as mentioned, the Pannys are a good bang for the buck. If you can wait a couple or three months, the OPPO unit will be out, as well. I can't stand the PS3, but that's me. I don't game, so it's of no advantage to me plus I just really don't like the way it looks. Yes, I had one and sold it about 1-2 weeks after buying it.
I have the Pio 1150, also. It is a fantastic display, even if they are "only" 768p. Pioneer is a great company and supports it's products well. They keep up with firmware upgrades, so don't worry. One other thing to keep in mind is that both of the Pio units are profile 1.1. If you value 2.0 (BD live capability) then buy something else. I couldn't care less, so 1.1 is fine by me.
Good luck with your purchase and enjoy HD!