Planters with Flowers

I really want to get a planter and put flowers or herbs in it.  It would sit on the ledge right outside on our front porch.  I think a long, rectangular one would look great because the space is slim and long.
Something like these:

I need suggestions on what flowers to use or herbs.  It is in the shade but gets some sun light.  If anyone has experience with growing flowers outside let me know what has and hasn't worked for you!!

Hope everyone had a lovely Easter!