Botman was asked if they know what the recommended specs would be for A:CM, he said they don't know yet, but they will probably be similar to what Borderlands had.
Intel Processor - Pentium 4 2.4GHz
AMD Processor - Athlon XP 2400+
Nvidia Graphics Card - GeForce 8600 GS
ATI Graphics Card - Radeon X850 Series
RAM Memory - 2 GB
Hard Disk Space - 8 GB
Direct X - 9
Also he confirmed that A:CM won't support DX11 and would look the same on a DX9 and DX11 cards.