Not sure if those of you who already have one of these will know this, but my pass is due for renewal in a couple of weeks, and the National Rail site now has a special offer - if you renew for 3 years, you save £20, it only costs you £70 instead of £90. I've gone for the offer - who knows how much they might hike the price for us before 2017!
I renewed my last week but decided against the three-year offer - I must admit I hadn't thought of the possibility of a price rise. Still very good value though, I save well over £200 every year.