AMD. The core 2 duo is dead-end technology with no upgrade path, and the i3 is too expensive to throw away on a future i5 or i7 upgrade. AMD's socket AM3 does offer an upgrade path, and the entry-level CPUs are cheap. For $100 though, you can get an Athlon II X4. What is your total budget, and what resolution is your monitor?
The mobo looks ok on a budget (although with 16x,4x it won't be good for Crossfire), but I don't like the CPU. For that price, get a X3, or spend another $12-$13 and get a X4. The RAM is ok, but get two sticks.