A Little Edgy

After clearing much of the garden pathway for the formal front garden, we find ourselves contemplating what edging material to use. In the knot garden, the path is pea gravel and the edge is brick. But all those bricks were just stacked up in the garage and came to us at no cost. (We did have to buy the house to get them but the roses alone made that purchase worthwhile.)
Do we continue the look and spend the money on bricks? Saw a nice metal edging in brown at Lowe's this weekend that was affordable. We're pretty set against plastic or cheesy looking stuff. And with 100 feet to edge, more than a couple packets will do.
One other thought was to mix our own concrete, add coloring and create a custom concrete edge. It seems to be all the rage among landscaping companies at the home shows.
So what do you think?