I'm going to tick off a lot of people for this one, but - don't give them access to "free" magic.
Let me explain - First off, there are no magic item shops in the world I co-run, why, because it makes magic items special. (Player: Gee, this +1 longsword just doesn't do it for me anymore. Salesperson: How about this +3 flaming, voropal model? Player: OOOOOOHHHHH!)
Secondly - be very descriptive when telling them what they find - instead of a small gold crown, try, "you find a gold circlet of approximately 12" in diameter. There is a single small emerald chip on the front, round cut and set in a scalloped, wire base. The head that would have been adorned by this crownlet would have had to have been quite large."
Not only will they wonder if the thing is magical, they will begin to research what could have worn a crown that large. If the pursue it, it may open up a whole new story arch you never would have thought about. (Great for side adventures and one offs.)
Thirdly - Believe that the items are worth handing out in the first place. A lot of DMs I have played with were completely thrown off when my character would take a seemingly "useless or valueless" item and make it my prize possession. They had thrown the item in as a "just junk" or filler material and I took it to the next level. As a fellow DM, I knew the value in it, it creates story, adds atmosphere and ellicits Roleplaying from even the most staunch hack & slay player.
As for examples - The current characters in the campaign I'm running are carrying the following "mundane" items:
1) 5 bottles of 400 year old wine - waiting to complete their current quest and are saving it for the celebration. (They thought of that on their own)
2) Platinum Ferrionier with a ruby jewel - used as part of disguise by the poor sorceress to gain a situational modifier when meeting royalty.
3) Book of arcane research - no real game value, but the mage is always reading it in the off time - first book she grabs. (My fellow DM and I are keeping track and when she logs 20 hours of off time research, we are going to give her a +2 skill bonus to arcane knowledge as a roleplaying reward)
4) Painting of a relative of one of the PCs - They found this in a crawl, it was the great, great grandfather of one of the parties paladins. It now resides in his room as a symbol of the greatness he too wishes to achieve in the name of his faith.
None of these items were considered to be "great" treasures when I made them, but each item, because of the way the players made them live makes each item great treasures.