I definitely use reversals. It can show a kind of superficial or mendacious flavour to the card's meaning (e.g. the Four of Swords came up reversed for someone who was supposedly on sick leave but actually using it to campaign in the local elections) or else provide a clue as to the feelings of the characters in the cards.
One time I did "turn negatives into positives" for someone, as the cards themselves seemed to think that if the querent took the advice given by the reversed card, the positive aspects of the cards would make themselves known. But last night someone's spread came up reversed, and the reversals made more sense than the cards would have done if it had come up right way round - a reversed Devil card showed her conquering her addictions. (Mind you the deck, the Archeon, was being very very cheeky by showing people who were slightly nervous about tarot all the "nasty" cards...I think that deck will need some serious grounding before I show it to anyone else as last night's spread was done in front of someone from church who was not at all sure about having a reading done and definitely not happy when Death and the Devil came up in the spreads I did for the others! I made sure I "smudged" it when I got home and it behaved itself when I dowsed for some stamps I needed to send one of my customers but which my mother had thoughtfully cleared away somewhere...)
Since I do readings from intuition vis-a-vis the design on the cards, Cups reversed tend to suggest leakages or pouring away of the bounty stored in them, particularly if the card is a good one (such as the bird on the Ace of Cups reversed is clinging on for dear life as the cup spins upside down; the Ten of Cups reversed represented for me once a very literal pouring away of tea from a cup when it was too hot to have a hot drink in the first place but no-one would clear up a half-full cup!). In a dowsing spread, reversed wands (even e.g. the pole on the Fool card) or swords are helpful since they usually "point" to the lost object in question.
So reversed cards add a depth and a breadth to my readings.
The lady whose cards came up reversed was left-handed and mentioned this but I reassured her that I too am left-handed and it doesn't always happen for me (in fact, of course, she'd just seen me read for the other lady without any reversals at all).
Glad someone revived this old thread, BTW, I started one on Talking Tarot but this is obviously a better place for it.