I finished the retaining wall last week, using the interlocking blocks. They are more expensive than wood, but I know they will last.

The trick with these blocks is to install them precisely level on the first row. If the 1st row is out of alignment, the imperfection will 'telegraph' up through the rest of the rows and be quite visible as you move upwards.

I installed the blocks, plus a french drain behind the blocks, and another french drain along that walkway between the house and the wall. The french drain pipes were wrapped in landscape fabric and surrounded by gravel, at a 2 percent slope.

Here is a picture with the wall finished.