I prefer OSDs that keep things simple - up and down to select the item, left and right to change the item's value. Most monitors these days seem to have things grouped, which means fumbling for two more buttons - one to enter the submenu and another to come back out.
As for DDC-based control, this is great, assuming the manufacturers don't screw it up. My Dell 2407WFP-HC can be controlled via software, but they've messed up the brightness scale, so 0% in the software equals 30% on the monitor itself. 30% is already too bright (I keep it at between 10 and 20% unless it's really sunny outside), so the software control is useless to me.
And why can't we just have input selectors. Again, my Dell monitor cycles VGA->DVI->Component->Composite-SVideo. I only use DVI (for the PC) and VGA (for the Xbox 360) but I have to cycle through every one to get back to VGA after using DVI. I know it's not a big deal, but it's extra wear and tear on the little plastic button.