Right, a reference model of the card is the card exactly as ATI designed it. There are now, as you said, a few models appearing with the same sillicon, but the new egg-shaped cooler. There is little information about the performance of the newer cooler, but I would assume it performs equally or better to the original cooler.
A non reference card is a card which, apart from having the same chip soldered in, doesn't bare much resemblance to the reference model. It might have a better cooling system, will likely have a totally different layout of components on the board and is probably factory overclocked. They advantages over the reference board, such as very quiet running or high clocks from the factory/easier to get to higher clocks.
If you buy a reference card, it'll be the same no matter what company you buy it from (so warranty should be your deciding factor). I noticed all the cards you listed are from XFX - any particular reason why? Regarding non reference cards, just do your research and decide if one is right for you.
It is worth bearing in mind that many non-refence cards do not have the ability to overvolt the card through software, as exhibited in the standard versions. Again, if that matters to you, do your research.
ADDENDUM: Looking at some of your models, cards with the name of a game afterwards are normally the reference card with a free game thrown in.
Called XFX and got the straight skinny... Here it is for people in the same "boat" and need help.
HD-585A-ZNFV is ATI Refrence with shroud(enclosed) cooler with fan on the end
The rest of HD-585X ones are XFX version of the card Non-Ref
Ones with ZNF have the shroud(enclosed) cooler with fan in the middle
Ones with ZNF Have the Egg cooler
Dude said that 585X are for basiclly if you want to slap on a block for water cooling, because of the placement of chips and such on the 585A (ATI ref) are really close to the GPU/water block placment.
As far as coolers go, I'd just want whatever keeps the GPU itself the coolest.
Couple Points for you to consider:
Reference coolers are designed to blow ALL the air out the rear of the case (through the PCI expansion slots). This is very good for cases that already have poor air flow.
Aftermarket coolers in many cases do not blow the air out of the case. These may cool the GPU better, but you also need to make sure you have good air intake and exhaust out of your case. That way you don't heat up the inside of your case over prolonged periods.
I'm going with the Egg cooler for better GPU cooling since my case is a wind tunnel and will spit out warm air this cooler throws in.
I'm going with XFX because of double lifetime warranty. In case of it breaking or if I decide to upgrade the card has a high resale value to others because the lifetime warranty transfers to them aswell.
As Willakan stated I think the 585X (non ref) cards have alittle higher clock speeds. Don't me on it %100 tho.
Just received the ZNFC model I bought from the 'Egg for $279 + a free 8G OCZ flash drive! Will install tonight and share my results sometime next week as my weekend is just crammed. And yeah, you can't beat the transferrable XFX warranty. Even EVGA's warranty isn't transferrable, and of course, they only deal in nVidia product.
Currently running 2 of these in crossfire mode with XFX HD 5870 bioses at 850/4800(1200). Added copper heatsinks to memory and reseated GPU's with TX-4. Amazing performance folks, and I'm still running a Q9550 at 3.825 on a P45 platform (ASUS P5Q-Deluxe). Vantage/Unigine temps never even hit above 65C.