I find pots a PITA to keep watered and try to minimize the number I use! But a gardener I met through a GW forum has an incredibly elaborate border in pots along her driveway. She is also in a relatively cold zone and needs to bring things indoors for the winter. It must be a crazy amount of work but looks pretty good (see link to a picture from Aug. 2011) so it can be done if you don't mind the work...

Here is a link that might be useful: {{gwi:13643}}

What you might think to be a "cute" idea would probably become unsatisfactory in short order. But people make borders of all manner of things - colored wine or beer bottles buried neck side down to mention but one.

If you've got a collection of clay pots - make yourself a little trial border and be the judge of your own creativity and how much extra maintenance work all that creativity will involve. Probably no more annoying to weed-whack around than the row of rocks people often use as borders.