Assistance Needed Please

Ok, I am looking at 3 CPU's to purchase. I want a laptop that will game fairly well. The 3 CPU's I am looking at have the following equipment.

Laptop #1. Intel Core Duo P8400 @ 2.26GHZ, 4GB of Memory, Vistas (64-bit), dual 512MB ATI HD 3870 (crossfire enabled) vid card, 17 inch display @ 1920x1200 resolution, hard drive=160GB @7200RPM. Cost $2100.00

Laptop #2. Intel Core Duo T7200 @ 2.0GHZ, 4GB of Memory, Vistas (64-bit), dual 512BM Nvidia 8700GT (SLI enabled vid card, 17 inch display @ 1920x1200 resolution, hard drive=160GB @7200 RPM. Cost $1900.00

Laptop #3. Intel Core Duo 7200 @ 2.0GHZ, 3gGB of Memory, Vistas (32-bit), dual 512MB Nvidia 7950GTX (SLI enabled) vid card, 17 inch display @ 1440x900 resolution, hard drive=160GB @ 7200 RPM. Cost $1630.00

I mainly play Halo, Call of Duty, Medal of Honor, Madden and Star Wars games on my CPU. So I need to find a good deal that won't kill me in the long run. My questions are as follows.

#1. Do I need dual graphics cards or is 1 512MB graphics card sufficient?

#2. Is Vistas 64bit any better than 32bit other than the fact that 32 bit will not support > 3GB of memory?

#3. Is ATI better than Nvidia with Vistas? I have had problems with my Nvidia card on a system with Vistas 32 bit and was told that Nvidia is having alot of driving issues with Vistas.

#4. Of the above laptops, which is the best overall deal? I mean for package and price. I can see the cheapest but that doesn't necessarily make it the best option in the long run.

Thanks for you help folks.