It doesn't matter how long you have been riding, or how much experience you have, it can happen to you.
I decided I'd take the bike to work yesterday (I commute from Biddulph to Manchester) - first day out this year, snow gone, frost lifted etc.
Travelling slowly (about 20 mph or so) along a narrow country lane, about 3 miles from home, just coming out of a l/h bend over the brow of a small incline, I hit a patch of black ice and found myself on the deck.
I had no warning and no time to react, the front wheel lost grip and down we went - I just let go of the bike as I hit the road and watched helplessly as she slid along on her side for another 20-30 yards or so. 
Nice new large l/h pannier very battered, lost the mirror, smashed the crash bar cover and leg shield, bent the crash bar and cracked the fairing - nothing major broken or bent, though. I ripped a hole in my waterproofs (the leathers were unmarked) and bruised my hip, guess that hit the road first, and my pride - my first 'off' on the road in 30 years - bugger! Other than that, I was fine, thanks to wearing the right gear.
Anyway, I picked her up, put the broken bits in the topbox, started her up again and rode back home. You can't do that with many bikes these days - Honda Deauvilles are solid lumps!
So I guess the moral of the story is that it really can happen to anyone - so always be prepared for the unexpected and never go out without wearing proper protective clothing.
and glad you are ok 
