I would never live anywhere the forced me to have one bike but if I had to have only one bike it would be a nice road bike. If an mtb then a nice steel hardtail (Soul) – or a toughish Ti (On-one?).

But then my most versatile bike is my slidey drop out Inbred – I've happily used it for offroad, road touring and as SS.

A comfy HT that is at home on 5 hour rides including longish climbs, singletrack and easy DH trails.

Adjustable travel 6-4" bolt-thru air fork, reasonably slacked out at full extension. Largish volume, med tread, LUST tyres on medium width rims on Pro2's. A comfy saddle on a 4" adjustable seatpost. Relatively short chainstays. Med-wide low bars and a stiff shortish stem, 18 speed. Target weight of 28lb.

Two i'm looking at is a Tomac Snyper and one of the new SantaCruz Nickle

I have only one bike and it's a Zesty. Light enough for long rides but plenty of fun when gravity is on your side.

If you want a true "do everything" bike, then a hardtail or cyclocross would probably be more suitable. Sounds like you want a true off-road all rounder though, not one bike for absolutely everything, so I'd suggest a light weight 120-140mm full-suss is not a bad decision.

Personally I'm very happy with my Zesty for covering everything I'll ever want to do on a mountain bike but I'm really hankering after one of those 2011 Genesis Day One Cross bikes with an Alfine hub to cover the rest of the spectrum (commuting – road – off-road pottling etc).

Turner DWlink 5spot or SC Heckler

For a start the forks would go.. Lyrik Coil Uturns (max length 160mm not 170)
the rest of the kit looks spot. (my wheels are pro2s with Mavic EN321)
Orange 5 simple.

I have my 5 set up like this, I can take it anywhere in the world and it will cope –
Long XC ride wind the forks to appropriate height and away I go..
get to a super gnarly/techie descent – wind the forks back out and away I go.
I went to Central Canada a few years ago – mainly riding XC a few hours north of Toronto, with occasional woodwork thru the trees with drops – plus spent a long weeeknd in Bromont riding the trails (inc world cup course) my bike was very very versatile and only twice on the DH black runs at Bromont did I feel under biked.