Hey, you guys change colours faster than a chameleon!
But I think that grey or black would be bad choices... in any dark corner, black would be invisible. And bearing in mind that on many (most?) maps, greyish tones are predominant (concrete and stuff), I wouldn't take grey, either.
To something different: As I mentioned, the pointing help is really great, and so is the fixed waypoint check! I was about to teleport to the corresponding waypoint a minute ago while fixing a map, but then I noticed that I already was at the correct point - fantastic!
The only downside is that after a mapchange with WP on both my CS 1.5 and CS 1.6 crash. Let's say I have finished waypointing a map and afterwards I'd like to switch to a second one to remove some errors I found. I have waypoint editing mode on all the time while I'm on map A, save my stuff when I'm finished, leave waypointing mode on and switch to map B. Map B loads, shows up on screen (waypoints, too, being displayed), and when I start moving around, CS crashes (1.5). On 1.6, the crash can even occur before the map shows on my screen.