If you are looking for retaining wall ideas, consider natural stone if it fits in with your budget. However, if not, take a look at some of these block designs, especially the modular ones that mimic stone.
I think the following are some excellent considerations.
Beautiful Stone Wall With Large Stone Insets
I would have to say that this is my favorite type of wall (although I like face stone walls to, as can be seen here. Stone Retaining Wall Ideas The small boulder type rocks create such interest and also breaks up the expanse.
Leave pockets in dry laid walls to place plants in to soften the stone and add some plants in front also.
Stone wall with bluestone or limestone top.
If you are going to use the wall as a seat wall, it's nice to have smooth surface to sit on and bluestone or limestone is a good choice. It is more expensive however than just using ths same types of stone as the wall as seen in the next photo.
Stone Retaining Wall With Individual Stones as Top Coping
This is the same type of wall but with even larger boulders used with the other stones. The wall coping is more casual but still great looking.
Modular Block Wall
There are a few reason to use a decorative block wall rather than natural stone, but the most common reason is that it is less expensive. It also goes well with certain pavers. This one shown above is my favorite type of block wall because I feel it is the one that does the best job of resembling natural stone.
A Less Expensive Choice For a Wall
This is also a block wall (man-made). However, all the pieces are the same size. For a bit more money you can have one that is better looking. However, sometimes a retaining wall is situated so that you are really not going to see much of it...and in that case, use this type to save some money.
You can also cover a wall with plants so that it is almost completely hidden.