I can't get graphics working on my system, it seems impossible so I gave up.
What graphics card do you have? Most get it wrong by trying to install drivers - especially those that come with a distro (NVDarwin, NVkush etc.). Drivers / kext's are not the right way to go. Use OSX86 Tools to generate EFI strings for your graphics card which are then added to com.apple.boot.plist file. Thats all you need. If there are no standard strings avaialble, you can create a custom string relevant to your specific card. Have you tried google...it's your friend and it works!
Any 6000 series and up nvidia PCI E card will work in Leopard - not in Snow Leopard though (only 9000 series and up after the 10.6.2 update).
The most common problem after getting your g/card to work (blue screen or monitor goes into power saving mode) , is that you need to connect your monitor (LCD) via the hdi port instead of vga. (use the vga to hdi adaptor which came with your card)
If resolution is a problem, add the resolution you would like to apple.boot.plist eg. <string>-x32 "Graphics Mode"="1400x900x32@60"</string> The 60 is the refresh rate. The default was 70 which caused my display to go into standby mode. this string forces it to use 60 as refresh rate
PS: Onboard graphics won't work in hq mode - ever. You need a stand-alone graphics card.