I don't think MW2 effected UC2 sales very much, although they were released 1 month apart not in the span of 1 week like MW3 and UC3. 

I think Uncharted 3 has a lot more broad-based appeal than BF3.  I actually don't expect BF3 to sell a ton more than Bad Company 2 did, especially on the PS3.  I still have yet to see how BF3 will be vastly superior game than BF:BC2 on consoles.  On PC BF3 will be a beast, but I'm sure it is going to be that much more spectacular than BF:BC2 on console. 

about a week before U3 comes out I will put "buy U3 or I'll delete u" for my comment title on my PS3! :p

If anything UC3 is the potential distruptor. I think MW3 and BF3 sales on PS3 will be a bit lower against the 360 version that one might otherwise expect because UC3 will have PS3 gamers drooling and thinking they can get BF3 or MW3 a little bit later.

At least that's what I hope.

I'm getting UC3 week 1. And that's something I've never done before for myself (I've bought games week 1 for other people's birthday presents and such).

Haha good stuff!

I think it's different enough that it has its own fanbase.

Besides, I'm getting BF3 and maybe (if it returns to its former glory) MW3 on PC.