I've had some odd problems with video too. I can set it up with my old 17" monitor to run at 800x600 just fine, but it refuses to go past 640x480 on my 50" Toshiba HDTV. I'm using the S-Video out, though the cable ain't the greatest. Any thoughts?
Also, it seems like I'm getting a lot of RF interference... there's these nasty diagonal lines, but they mostly only show up on the lighter colors... and every once in a while, the screen will flicker... usually when I hear the HDD accessed, but not always.
BTW: I have an ISA HDD adapter,with the HDD outside the box, housed in a dataport I had laying around.