About colliding visual scan and such, sometimes I spot a cessna 172 at 5 miles, sometimes I cannot find a MD88 2 miles 12 o'c co-alt. The sky works it's misterious ways indeed.
On a side note, when I fly the C210, C402, the C412 I look outside almost constantly. When I fly the Metro, I found myself barely looking ahead of me, which made me realized I became more "unsafe". It's due to the position of the seat, in the Metro, I have this big dash ahead of me that greatly reduces my foward vis. If I raise my seat to get some kind of foward vis, then I cannot see the top row of my instruments, nor the radios. To make matters worse, the Metro is very sensitive in pitch and only a couple of seconds of distraction will get you +/- 500ft, thus you stare at those instruments often.
I also recall a collision between the single engine Cessna, and a B737, where the Cessna pilot didn't see the B737 coming from his 3 O'c. The planes coming straight at you are hard to see as they appear to not move, compared to the ones crossing your field of vision.