I like Jennifer's edging as well,
One garden has some river rocks as a path/dividing line to keep lilies separated from other plants because I don't like looking at their bare stems for months. They need lifting every few years because they sink, like Rose said.
We had the black edging with the rolled top (a haven for slugs) for many years and I had more of it ripped out in January. I may replace it with bricks, set dogtooth style, or may just let it be since it's out of my view. The one garden where I did use the bricks is doing well.
We bought an entire pallette of stones in 2012 and I used them to edge many gardens. So far, so good. I used the cobrahead weeder and that was a huge help in keeping things neat.
Deb - for the area you showed in the above photos you could use some Envirotiles (sold at Home Depot) after you've weeded it, then pile on some nice neat mulch of your choice so they won't be on view but will keep it weed free. They can be cut (I've never had to try it) to fit.
Our next door neighbor doesn't weed, he weed whacks and all the weed seeds land on our side. This was the only solution I found that worked for me.