Right - the drivers.
I don't know what EMI and Safety is and you'd probably get a newer audio driver from Realtek, but download the Win 7 x64 bit ones from there after the upgrade and then either Device Manager or Slimdrivers will find you an updated version.
If everything works okay after the upgrade then I'd leave the BIOS upgrade alone.
The VGA Nvidia driver - only get that from the support site, although Device Manager could find something for that after.
I wouldn't bother with the Modem driver, but if that's your Card Reader model then download that.
You'll want the Touchpad drivers and only anything which relates to Win 7 under Utilities.
As for the Wireless driver, you will need to go into Device Manager/Network adapters - right click on it and select Properties and under the Details tab, use the dropdown and select Hardware Ids.
There you will see a VEN & DEV No. which you can compare to those listed, but I don't know yet where you can find this Wireless Console Utility which is a pre-requirement.
You may have to contact Asus support for that before you upgrade.
The Bluetooth driver should be okay, but you will need to ID the VEN & DEV No. for the camera the same way for its drivers.
Those under Others should be okay as they are listed for Win 7 x64.
Now for the Custom install - it's always best to create a full external system image first so you will have a fall back and if that has been stored onto an external HDD then you will need to create a Repair Disk before hand to boot up with, so as to select Repair your Computer to navigate to the Recovery Environment to select the restore from the one I'd made earlier option.
You will need to change the Boot order for that and for the Custom install to boot up with the SP1 install disk.
When you eventually get to the Splash screen, select Install and from what I remember, it pretty well does it itself after you select Custom Install and you should opt to install it over Vista in C:\.
This will create a Windows.old file of many GBS which can be deleted later if has gone well.
You will need to do the Custom rather than Upgrade as you are going from a 32 bit system to a 64 bit system.
I've been looking for some tutorials but so far have only found blogs without any "walk-throughs".