Which VGA BIOS are you using?
The VGA BIOS in my signature that myself and Xman954 built has the 'Force Progressive' (Force480p basically) which usually has the best results. Or, you can also try using my VGA Boot Disc which is based on the same BIOS as above, which also supports Force Progressive.
NOTE: The 470k resistors seem to have the best results overall, I would recommend sticking with those.
NOTE 2: If all else fails Divineo.com offers the 'Frozen Cable' for $19.99 which is the based on the LM1881N VGA cable diagram, you might want to consider getting one simply for testing. I don't personally profit from the sales of these cables myself whatsoever, I actually always recommend people build things like this themselves simply for the experience, but it may be helpful in figuring out if it is truly your cable or the monitor.

NOTE 3: 480p is required for VGA to function properly on the XBOX with any VGA BIOS (including my VGA patchers) (except for the BIOS that myself and Xman954 created, it is the exception as it forces progressive scan anyway), so always make sure that it is turned on in your Microsoft Dashboard. (I recommend though that you leave 720p and 1080i turned off until you are sure everything is working properly though.)
I am using "FrostyTheSnowman and Xman954's X2 5035 VGA BIOS v1.0" that I got from the usual places and flashed it to one half of my TSOP leaving the other half with X2 5035 Non VGA Bios. I flip a switch to select between the 2.
not sure what else it might be. seems that the LM1881N chip is working though because the status of my monitor is changing now. It thinks it is in power save mode when I turn the 360 on with the VGA BIOs selected and then if I turn it on with the normal non VGA BIOs it acts like it is going to show something but doesnt just "Out of Range" but sometimes I was able to get it to show the dash in all green without the VGA Bios. May just be that my Dell Monitor doesnt like the xbox on it. My 360 is happy with it. I dont even use the monitor for a PC anymore it is in my sons room for gaming. I was going to get a switch box to switch between the 360 and the xbox. For now I have a Apple Monitor 20inch and the Dell in their just that the Dell is a LCD and the Apple is CRT and very space consuming. If you think of anything else please let me know. Thanks a lot for all your help.