For some ideas you can scroll down to the bottom of the page, choose P then pond ideas and you'll find lots of members ideas to browse

If your pond is going to look fairly formal then good stone paving slabs will look effective. Ours, which is more of a natural/wildlife pond, has local stone around it. You can also have grass up to the edge of your pond though you need to be careful when mowing or flower beds with gaps for seats or access. It is really down to you what you want to make it... I've seen Show Gardens at Gardening Scotland with railway sleepers used as a surround, ironwork, brickwork - you name it... depends what the rest of your garden is like and how formal/informal it is.