I have just been to Christchurch, NZ, and there are amazing rides on the Port Hills right close to the city. Easy access, great scenery, mtb parks with dh shuttle bus service if you want.

Have a look:

http://youtu.be/Dg6aUK3cqbQ

http://www.ccc.govt.nz/cycling/TracksRides/PortH...

And a wonderful singlespeed shop if that's your bag - www.grindbikes.co.nz (great bikes but get your coffee at the Lyttelton Coffee Company). Paste the links.