I'm looking for ways to optimize Debian for my Intel Core i7-2600 system with 8 GB of memory and Asus ENGTX560 Top. Having used Gentoo before Debian I'm still used to optimize my system. I might even install Gentoo just to see how long an emerge world will take :-D

First choice is 32 or 64-bit. I prefer 32-bit with pae because a lot of proprietary games are still 32-bit. And vanilla Firefox and Thunderbird can be easily installed as well. Are there any advantages running 64-bit or is the performance still similar to 32-bit?

Next I'm thinking of tweaking the kernel setting the following options:
Processor type and features  ---> 
     Processor family (Core 2/newer Xeon)  --->       
Preemption Model (Preemptible Kernel (Low-Latency Desktop))
Timer frequency (1000 HZ)  --->
If I'm not mistaken these will enhance the performance of my system. Are there any options that can be tweaked in the kernel?

The benchmarks o Phoronix tend to show that it's best to have the latest version versions of software, therefor I'll run Debian testing. What else can I do to optimize Debian for my system?