Current list stands on: 

360 3rd Party Exclusives:

1. Start Ocean 4
2. The Last Remnant
3. Kill All Humans
4. Left 4 Dead
5. C&C Red Alert
6. Splinter cell conviction.

PS3 3rd Party Exclsuive:

1. Valkyria Chronicals
2. FF XIII VS.
3. Quantom Theory
4. Yakuza 3

Heavy Rain is being published by Sony, but I really don't see the point of this list, the vast majority of third party games are multiplatform, and the vast majority of exclusive games are first party. The handful of games which are third party and exclusive are fairly irrelevant, and most of those are only timed exclusive too.

As long as every platform is getting all of the 3rd parties (or the vast majority of those) then none of the platforms is at risk of sinking into a death spriral. It is pretty obvious that right now both the 360 and PS3 are very vialable platforms and the very short list of 3rd party exlusives (for each side) proves the point pretty well. As long as this holds true this excercise might seem a bit boring, espacially when fanboy opinions on the quality of these titles is discouraged in this thread.

But this equilibrium can change. 3rd party support might drop for one of the platform at some point. The list will allow us to track and detect such a trend. You need to be patient here. No astounding insight is going to be unearth by the list in the next few weeks. But give us a few months and something interesting might develop. At this early stage I want to establish an accurate baseline for the tracking process.

Makes sense?

I ust don't see it happening, installed base isn't low enough to ignore either platform on a Global basis, the vast majority of games will be multi-platform for the remainder of this generation. The only exception will be region specific releases which you have excluded.

Anyway, Disgaea 3 will be released in Europe early 2009, thus qualifying under your "must be released in Americas and Others" rule.

Current list stands on: 

360 3rd Party Exclusives:

1. Start Ocean 4
2. The Last Remnant
3. Kill All Humans
4. Left 4 Dead
5. C&C Red Alert
6. Splinter cell conviction.

PS3 3rd Party Exclsuive:

1. Valkyria Chronicals
2. FF XIII VS.
3. Quantom Theory
4. Yakuza 3
5. Disgaea 3 (PAL only)

Kill All Humans(Destroy All Humans) is coming to Europe on the ps3 btw but not NA

http://www.ps3fanboy.com/2008/11/28/destroy-all-humans-path-of-the-furon-will-come-to-europe/

Yeah, but fails to qualify under:

a) releases that cover at least the two large markets of Americas and Others
b) We’ll consider a release as being exclusive to the platform if it does not show-up on the other platform within the one month time window.

We don't often see things happening before they happen. Who could have foreseen the Wii phenomenon? Who thought three months ago that the 360 will crush the PS3 this holiday season? The FF XIII was a shocking announcemet, right?

BKK2, here is a scenario for you: If the 360 will continue to outsell the PS3 at the current pace for several more months, many small developers with limited budgets may start doing do the following math:

PS3 = small and dwindling market share + difficult development & bad tools + no-so-great attach rate + prolonged release process.

For them, it might just be worth to skip the PS3, develop with the great tools Microsoft provides as native 360 title with no compromises, finish early, release early and enjoy the great attach rate of the 360.

Right now it isn't happenning often. "Kill all humans" was such a case though. However, with the current economic climate where capital is drying out we might see more small-time-titles be forced into finishing the release on a smaller budget and that may mean cutting support for their non-leading platform. They may even get concessions from the platform owner for granting them the exclusivity (shared promotions or lower royalties).

Can you now see something like this happening? At least in theory?

P.S. thanks for the title info. The list is updated.

"Except Kill all Humans is still in development for PS3, it's just been delayed until next year."

Which exactly demonstrates the point. A small budget title cannot hold its financial breath until the PS3 port is ready. So the title is choosing to release first on the 360, get some cash flow going and use it to finish the port for the PS3.

This may become the story with many smaller development studios. Taking on a dual platform release may strain them financially, especially if they need to start cutting back based on the economic situation. Releasing first on the first platform that is ready may seem like a reasonable method of operation for them.

If this happens, one of the platforms will start getting the titles early and the others will get them months later, which means an effective time exclusive.