Just to start, I'll list my specs:
CPU: Intel i7 940
Mobo: MSI Eclipse SLi (X58)
RAM: 12 GB DDR3
Graphics: ATI Radeon HD 4870
Sound: Creative Sound Blaster X-Fi
I've tried various installation methods, but this is the only one that has worked thus far. I downloaded and burned iPC 10.5.6 universal final, and from the iPC installer I partitioned the a separate hard drive into two partitions (one small 15GB for the iPC installation, and the rest for the snow leopard installation). The first problem was booting into the iPC installer. I had to use the following boot flags to boot successfully: cpus=1 busratio=22 -x32 -f -v. The busratio is dependent on your CPU. If you have the i7 920 I think the boot flag must be busratio=20. I am not sure about any other CPU. After iPC is installed, boot into it, and run the X58 Mobo Patch Installer (an amazing utility), which can be found here. Many thanks to digital dreamer for that little application . Just make sure you have the retail snow leopard disk in your DVD Drive when you run the installer. Also, there is an issue with the SATA controllers on this specific motherboard. There are two (ICH10R and JMicron). I am using the JMicron controller for my mac HDD and the SATA DVD Drive because I have the other controller set to RAID in the BIOS. As far as JMicron configuration goes in the BIOS, I just left the controller off and everything works perfectly. Also, after running the mobo patch installer, you have to install the kexts again from the program (for some reason it doesn't do it properly the first time). So just run all the install steps (1-7) and then run step 5 again. I changed which kexts I am using (basically deleted dsmos and sleepenabler...then installed fakesmc) so that I could update to 10.6.2 (which works for me). I attatched the list of kexts I have in S/L/E just to show what is needed. Also, here is a link to my current Extra folder in my root directory (including a patched DSDT) Extra Folder. Currently, everything is working (sound, ethernet, graphics) 100%. I used VoodooHDA for my sound card, and I deleted the old RealtekR1000.kext (it didn't work) and installed the latest version, which worked. Also, only kext helper b7 seemed to properly install the kexts, which kext utility did not. I'm not sure exactly why, but that was my experience. Also, use the attached bootloader. The Chameleon bootloader that came with the installer (#1) did not work and I haven't tried the second one (PC_EFI) but that's the one I choose during install. Basically, the attached bootloader is the only one I have had any success with. Install it to the iPC partition and you should be fine .
Sorry if I left anything out, and for the large chunk of text, but that's basically it.
Let me know if you want to see images/video of the OS, it's blazing fast =).