Cinder blocks! Great idea. I didn't use them, but if they're the kind with the holes, and you placed the hole side up that would be perfect for growing some of the herbs that root-propagate. Just fill the hole with some mel's mix* and the cinder blocks should keep them from taking over your garden. Whooly thyme would look great in a couple months, overflowing over the edges. Lemon balm, mint and oregano would be useful in addition to beautiful, but can grow taller than you may want.
*Many herbs prefer a poor soil. Mel's mix, with 1/3 compost, may be too rich.

Check out the Hypertufa forum. One of the posters here (Fuzzy) has a bed of cinderblocks coated with that and they look great.

Here is a link that might be useful: GW Hypertufa forum

I unintentionally buried my cinder blocks-- well to be honest the hail storm that washed away half of my yard this season partially buried them. But the other half of them is above ground and has made a beautiful planter for nasturtiums which trail over the edge and give me the added bonus of keeping bugs away and marigolds in between them. I just put garden soil in the holes and planted seeds or the annual starts in the holes.

I tried growing flowers in the holes of the cinderblocks, but it didn't work too well for me - got more weeds than flowers, and it made it harder to access the inner areas of the beds. So, we ended up putting cap blocks on them. The cinderblocks are gray, and the caps we got are about the same color as the bricks of our house. We've gotten lots of compliments from the neighbors about how nice it looks - plus, it makes it easier for me when I'm working out there....I can just sit down and relax for a little while if I want.

I used the scalloped edging and put a 1 foot area around my blocks and planted ground cover between the edging and the blocks. This does a great job hiding the blocks and makes an interesting contrast.

I have 3 huge raised beds out of cinder block (630 total blocks) and also thought they were ugly. I found a concrete stain that comes in various colors at home depot that worked really well (Behr brand) and used a cheap paint sprayer to apply, now they look like brick. Also of note, I did not do any of the prep work that the stain recommended (it becomes too expensive) and it is doing just fine, I did put on two coats though.

I also used the small holes for planting stawberries and herbs which makes it look really nice.

P.S. if you haven't already built your beds, split face cinder blocks look much nicer then the standard. They cost about 1.77 per block but it is worth in the long run as this can become a permanent structure.

I saw a cool trick on the TV the other day. Put moss (no soil) into a blender with either yogurt or buttermilk, puree and the paint onto the blocks. spray with water until the moss takes.

I still like the herb idea better but i thought i'd throw this out there.

Thanks to everyone who gave such attractive-sounding suggestions for affordable permanent raised beds!

I used them but first put layers of newspaper, about 6, on the ground before laying them out. It helped keep weeds from coming up into the main growing area and into the holes. I agree it's nice to cap at least a small area so there's a place to reach and sit.

I recently wrote about a gal who projected 65K gross from her 2 acres of cinder block gardens. Many of them are in greenhouses, so she gets sales for year-round fresh produce in Colorado. She has an inexpensive e-book on just how to build them and lay them out. It's at www.MicroEcoFarming.com, click on the 'Review of Market Garden Growing Techniques,' then scroll down to find the link to her Cinder Block Gardens book on the right.

Here is a link that might be useful: Center for the Micro Eco-Farming Movement

You should try mosaic-tiling them. That's what I do, and it looks beautiful. It does take some time, and creativity if your working on a specific design, but just about anyone can do something abstract. It is a great way to recycle glass bottles, broken plates, etc. Good Luck!!

I use the thin cinder blocks (4X8X16) and cap the top with cement bricks (2x4x8). All the holes are covered by the bricks. It has a finished look.