Pazar really caught my eye, it's snappy, catchy and rhymes with Bazaar. Therefore my vote would probably be for the slightly modified Pazaar. Not only a play on the English-ish Bazaar, but a subtle nod to the Pandora and also the Turkish word.
Not to purposely belittle anyone's, but the options available for voting seem to span from vague, to overly texty, to outright absurd. Pazaar has the benefit of being a relatively unused term (check google) although the .com is taken I imagine we're focussed on a .org.
OpenBox - Potentially confusing, a free window manager for X
Applace - Do we really want "Appl" in the name? Easily confused with an iPhone/iTouch project
Pandora's Box - Pretty good, actually, but too connected with the Pandora project and lacking in generecism (is that a word?)
Download Centre - Very descriptive, but dry and doesn't make for good desktop icon subtext
OpenMarket - Taken - http://www.openmarket.org/
Agora - ?! Reminds me of Agoraphobia... not a great connotation
Pandorium - Isn't that a fine establishment in the inner circles of hell? Oh, no, wait, it's that crappy resident evil knockoff film
The Centre - Center Centre... don't even touch that word
Open AppStore - I wonder how open it will really be, as closed source apps will be inevitably sold there. Also AppStore is again too iPhone/iPod/iPad connected
AppHole - ... ha!
PND - Really? pnd.org could work, I suppose if it wasn't taken
Appandora - Ahh my heid!
ARSE - Okay, now we're just being silly
Pazaar.org is available to register and really has the potential to be a brand in its own right. Just sayin'
*picks up phone... PAZZAAAAAAAAAAAAAAARRRR*