4-4-2 (preset 1 and 2) and 4-2-3-1 (preset 3 and 4)
Defenders in the middle between the midfield line and my own box line, backs halfway between the CD's and the midfield line. Midfielders a notch past the midfield line and the strikers on the penalty box line. AMC and LMF and RMF halfway between the opponent box line and the midfield line. I don't use DMC's at all, ever, as a CMF with A/D awareness 2/3 will work better. DMC movement and positioning is broken and they act like center backs.
Preset 1 and 3 / Preset 2 and 4
Support 8 / 14
Range 8 / 10
Switch 10 / 10
Style 9 / 11
Pressing 14 / 20
Line 12 / 12
Compactness 8 / 12
I usually leave attack and defense levels at default, because the formation is perfectly balanced as it is. I do change on corners, though, all the way to defensive and switch to full attack just before you hit the corner to create a lot of movement in the box. Remember to switch back to mid setting right away after the corner, or you will get in trouble. I also use "Switch wings" or whatever it's called, to create attacking width.
I have at least two identical formation presets with different strategy settings, as I actively change instructions during the match 5-10 times per half. If I smell a counter attack, I change to 14 Support, for example. Instead of "shutting up shop" I use normal Preset, and keep possession without any offensive movement towards the end of the match. I almost always use subs on the central midfielders, as they are vital for both attack and defense. Keep them fresh, and you will tear up the opposition. Attack/Defense awareness 3/2 and 2/3 (one of each*), Teamwork and Tenacity are the most important central midfielder abilities, everything else is more or less irrelevant.
*A/D awareness midfield comprised of 3/3 and 2/2 works as well, but the 3/3 guy needs to be subbed early in most cases.
Try it, and rule supreme!
EDIT:
I use this setup for ML, online and multiplayer. Any game mode, really.