Iron Grey Premium PLA. Low warp, easy to print.
This filament prints amazingly well, possibly the easiest to print with I have used.
The color is very pleasing, I have printed a few mechanical parts, and they have come out amazing.
see the photos in: http://www.thingiverse.com/thing:1642930
And a Moai statue: http://www.thingiverse.com/thing:144668
This PLA prints a little cooler than most others, on my machine as low as 180, in comparison to normal 195 - 210.
I would recommend PID tuning M303 S190, C8 as a matter of course,
which can help remove some of the 'wood grain effect'
One thing, it is slightly more flexible than the FilaPrint Ripe Orange Premium, which I love.