Recently I went on a long vacation, and though I was drinking coffee, it was no where near as much as usual, and even that trickled off completely during the last week. At that point I thought I may as well try stopping completely - it was hard, but it's been about a month now, and I definitely feel the better for it.
The main benefit is just being able to wake up easily in the morning - previously I would wake up and feel groggy for 30 minutes or so. I'd feel normal after 30 minutes whether I had a coffee or not, but it still made waking up unpleasant. Now, as soon as my alarm goes off (and usually 10 minutes before) I'm wide awake and feeling alert. It's seriously life changing - no more hitting snooze 17 times in a row...
The downside is, I miss the taste of coffee. There's some cereal drinks that make a passable drink, but they're like a watered down, bad tasting substitute for the real thing =/