Is there a use for the various ingots/ores apart from smithing?

Ores and ingots are only useful for smithing, though if you find a transmute spell you can turn iron and silver ore into gold, which is useful if you need some money. You can also sell ores to mine owners (usually they will only buy the type of ore their mines carry) at their full base price (unadjusted by your speechcraft skill, which is favorable), except for iron, which goes for 7 gold, while its base price is only 2.

Also, a few quests will require ore or ingots, but they are too few and far apart to justify the extra weight. Most, if not all of them, will be for gold or silver, so a quick trip to a blacksmith for iron ore and a few Transmute spells will do the trick.

This page may help you with determining if something is worth taking. They have many other similar pages on the site for other types of items as well. I usually pick up any ores, out of habit. They can be sold or used as weapon tempering if nothing else. Also, many ores and ingots are materials for the Atronach Forge.

Additionally, viewing the subpages for each material will give a much more detailed explanation.