Uncharted 3 is definitely the underdog. It's growing as a franchise and it is undoubtely the PS3's most anticipated exclusive. But Gears is the bigger franchise overall. So here's what I predict :

Uncharted 3 Lifetime : 6.0 - 6.5 Million
Gears of War 3 Lifetime : 7.5 - 8.0 Million

In terms of Metacritic / Gamerankings I expect Uncharted 3 and Gears 3 to be close to each other. But Uncharted 3 will come out on top :

Uncharted 3 : 95
Gears of War 3 : 92 - 93

Which franchise I like more ? It would have to be the Uncharted franchise by a long stretch. Although I plan on picking up the Gears collection right before Gears of War 3 comes out.

I'm pretty confident Gears of War 3 will outsell Uncharted 3 overall. Gears 1 and 2 suffered from being a bit rushed, and Gears 3 gets the longest development and testing time. So it's going to be noticably more polished then the other two, and both the sales of Gears 1 and 2, and strong pre-orders imply that Gears 3 will at least break 6 million lifetime. Uncharted 3 might be the biggest Uncharted in the franchise, but Uncharted 2 is still 1.7 million sales behind Gears, and it's going to be competing for attention with Resistance as well. So Uncharted 3 might break 5 million sales, but I really doubt it will pass Gears.

As for Week 1 sales, no PS3 exclusives have yet to record massive week 1 sales. Uncharted 2 only did 850k week 1, and Uncharted 1 did a measly 133k. Gears of War 2 did close to 2 million week 1, and Gears 1 did 910k. So even the debut title in 2006 had more sales (lifetime, and week 1) then Uncharted 2, arguably the best rated PS3 exclusive (alongside MGS4).

Personally I think Gears 3 has a shot for 7 million, 8 if CoD really drops the ball this year (Sledgehammer is developing, not Treyarch, or Infinity Ward and Activision has states they expect less volume). Uncharted 3 also has a shot for 5 million IMO, and it might crawl to 6 million if CoD drops the ball.

P.S. Judging from the relativly balanced votes for both games, and the inflated PS3 favoring audience on VGC, I think most people realize Gears will be bigger. I say inflated PS3 favoring audience based off the Most Wanted section when multiplatform games on PS3 get as much as 10x the votes of equivalent 360 titles or more.

most likely theyre people who arent members of this site, but post any way. 

i voted for gears but i think lifetime sales will be with .5 million of each other, with gears selling more

Gears 3 will sell more but Uncharted 3 will be the better game I think. 

Gears 3 without question.  It honestly probably won't even be close.  I expect there to be a minimum of 2 million units sales different between the two.

Honestly, I so want Uncharted to top-out since it is the underdog, and who doesn't like underdogs winning? Not this guy. Anywho, I expect Uncharted to have a coattail effect on its previous titles just as UC2 had on UC:DF. I believe that UC3 will bump UC2 by at least a million and UC1 by at least .5 mil. 

Will UC3 be the biggest in the series? Yes. Will it outsell UC2? Yes. Will it outsell Gears of War 3? No. For obvious reasons that have already been stated multiple times by numerous users. LOL, it would be kinda funny if GeOW3 sold 6.15 million LT. 

Looking at the poll results... really?!

You know guys, you're supposed to vote for what you think will happen, not what you wish would happen.

I'm all for being a fan, but that doesn't mean you have to blindly vote for your console of choice everywhere. There is really no point in making those polls anymore, because it just turns into a popularity contest.

I wish the community would mature to the point where we could have real polls with results that might have some value, because they reflect what people really think/expect and not what their inner fanboy tells them to vote.

Now this poll isn't the best example, since most people, who look at the sales data of the previous games and where the respective consoles stand right now, will predict the most likely outcome to be in favour of GeoW 3 - so there isn't much to be gained here information-wise.

There are however polls, which could have interesting results, but they always get tainted by fanboyism and therefore lose all relevance.

/rant

BTW: There should be a "show results"-button, so people don't have to vote multiple times just to see what the results are at the moment... or restrict the voting to users with accounts and let everyone only vote once.

ps: I hope this makes some sense ... grammar-wise. Even though I can understand English just fine, I'm always having trouble when it comes to writing stuff.

Gears 3 will outsell Gears 2, seriously. Gears 2 only did so "bad" because the multiplayer was pretty much unplayable except locally. When Gears 1 came it was the only great online game for 360 that was not Halo 2. Gears 3 will have dedicated servers, this alone even if the MP would be the same as Gears 2 MP is enough for some (myself included) but it also has 4 player co-op and probably a great campaign.

UC3 will probably do well, but i don't see how it will do better than UC2 when UC2 was bundled. Maybe UC3 will also be bundled, but PS3 slim was fresh when UC2 came. Now not many people will pick up the console for 1 game, if it is bundled though, it will sell well, maybe better than UC2 but not better than Gears 3. And if its not bundled there isn't even a competition.

Today:

I think the necro from that other thread is starting to go to bevo's head.