64-bit vs 32-bit

Hi Guys.

I never got into the Windows 7 Beta, and therefore got Windows 7 when it was fully released.

I knew about there being 2 different versions: 32- and 64-bit, and I did my research on how to find out what I'd be able to run.

I was running a 32-bit Windows Vista, and therefore got told by some members of a different forum to go for the 32-bit version of Windows 7. However, I've just looked at my detailed performance and system information for my laptop, and found out I can run 64-bit version of Windows 7:

System
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Manufacturer: Acer
Model: Aspire 5535
Total amount of system memory: 3.00 GB RAM
System type: 32-bit operating system
Number of processor cores: 2
64-bit capable: Yes

I have the backup discs for Windows 7, so I have discs for 32-bit version and 64-bit version.

My question is: How would my laptop improve if I went with the 64-bit version, and is it worth installing?

I only have 3 GB of RAM, and probably won't get any more.. But it's good that it can do more than 4 GB!

For your second point; does that mean programs, Windows, etc; will start-up and run quicker?

Thanks a lot. You've been a great help! +1 Rep.