When I bought my 12 plate Clio it cost me an extra £50 for a spare wheel, the weight of the spare  makes the car less fuel efficient, so instead you get an 'Inflation Kit'. 
My argument against that was, 'what happens if you rip out the side wall of the tyre?'  The answer was it's doesn't happen very often.
Earlier this week I heard of that happening to a local instructor, apparently he didn't even know he didn't have a spare just assumed he would have one.
Then reading the daily paper later that evening the RAC said that in the 12 months up to August 2013 it got 120,000 call out to  unrepairable punctures, none of which had a spare. 
I'm old fashioned and don't move with the times so I'll stick to having a boring spare!