Evening all, it seems odd my first post on a photo forum should be about mountain bikes :P I was about to put up a couple of portraits but got distracted by this thread as mountain biking is my other hobby and one I am probably much better at !
What sort of budget are you working with Paul ? Bikes are matched by camera's with their ability to soak up cash so it's generally a case of matching budget to the type and location of riding you think you will do, as people have said you'll always be served well by a descent hard tail if starting out and not wanting to outlay too much cash.
Something with a descent serviceable air sprung fork, hydraulic brakes, at least Shimano SLX / Sram S7 componentry will all be clues you're looking at something pretty reasonable for a starting point. Of course upgrades need to be done so you can start dropping weight with some new tyres and wheelset when funds or enthusiasm allow as these will be typical items the manufactures skimp on at that level. Ideally get something fairly light to start if you end up with a few options as it does make a difference on the trails, 12-13kg would be ideal.
If you go straight to a full suspension you won't be disappointed as long as you again match the machine to your intended riding and a reasonable spec, sounds like you're in the general trail / cross country camp so you'll be spoilt for choice !! The 120mm travel trail bike really is ideal for places like Rotorua / Woodhill and 90% of everything else (sorry I don't know where you are). With modern geometries and design they climb so so well and have plenty of 'get out of jail' potential on the down hill sections as well. Give GT a look as well (yes I'm biased as i have one :P), its not a boutique brand but they do make some excellent bikes all the same.
I hope thats of some use, post 1 ... complete