Mountain Biking - Whats a good bike for going up hill

Hi
I am 41 so I keep my downhill and jumping to a dull roar so that I dont' break anything
I do go uphills quite a bit to push myself
It is technical uphills that I like (roots, rocks, mud, varied slopes etc.)
The bike I have now is a Iron Horse Axion that is very lite at the back and keeps spining alot
I have some old box store bikes laying around and they have garbage tires and I can get up more technical hills because I can get the traction.
My question is: What is a good bike to get for going up hills
It has to be strong enough to take the technical trails I ride.
Thanks
Ps- Would a rigid bike climb better then a hard tail??

It's more about the technique than the bike. If you're riding slippery, technical trails with lots of roots and rocks (like here in Missouri!) first be sure you have good rubber. A good gnarly knobby will work wonders compared to the usual do-everything tires that come with most bikes.
Stopping wheelspin on uphills is a delicate balance. You have to keep your weight back enough to keep traction, and forward enough so as not to wheelie. (no steering with your front wheel in the air!)
On loose stuff, the usual technique is to grab those bar-ends (that's what they're for) and coordinate a sharp pull-back on the bars with each power stroke. That drives the rear wheel into the ground.
This is something that takes practice, but you can do it on pavement. It's a rapid, rythmic pulling in time with your pedal strokes.

Thanks for the tips
What kind of a bike should I get to provide max hilclimb ability.
My Iron Horse has a 2.10 nobby on it and my old bald tired boxstore bike can easily outdo it on a hill
The Iron Horse is great coming downhill but It really looses traction going up hill.
I think the Iron Horse was designed for downhill and trail.
Is there a bike out there for uphill and trail?

any decent hardtail should be a huge improvement in climbing... for even more improvement get a fork with a lockout or even a rigid one.

I RECOMMEND A FULL HARD TAIL FOR UP HILL COMBINED WITH WHAT FRANKEE SAID ...GOOD RUBBER. YOU DONT WANT TO LOSE TRACTION BUT YOU DONT WANT TO POP A WHEELEE EITHER. FOR ME IT'S PLENTY OF REV'S ON THE GRANNY GEARS WITH BODY FORWARD BUT NOT TOO MUCH, KEEP THE WEIGHT ON THE REAR FOR TRACTION,THE RAKE OF A SHOCK FORK IS DESIGNED TO GO DOWN HILL NOT UP, AN OLD FASHIONED SOLID FRONT FORK PUTS THE BIKE AT A MUCH BETTER CLIMBING ANGLE. THE PERFECT BIKE OF ALL TIME FOR WHAT YOUR DESCRIBING IS THE SPECIALIZED STUMPJUMPER FROM THE MID 80'S WITH THE CORRECT FRAME GEOMETRY AND NO SUSPENSION FRONT OR BACK TO ROB YOU OF YOUR POWER (SEE CRANK REV SHOCK BOUNCE) A TYPICAL DRAW BACK OF THE NEW FULL-SUSPENSION MACHINES,(THAT AND THE FACT THAT THEY ARE TANKS)COMPARED TO THE LIGHT AND NIMBLE FAST, TRAIL, HARD TAIL PRE-SUSPENSION MODELS OF THE MID 80,S. NEVER A FASTER BIKE BUILT, WHY, THEY HAD ROAD BIKE FRAME GEOMETRY.
TODAYS SMALLER FRAMES, THREADLESS HEAD SETS, PUTS THE RIDERS BUTT WAY IN THE SKY WHILE THE BARS ARE WAY TOO LOW. IN THE OLD DAYS, IF A SEATPOST WAS EXTENDED BEYOND 5 INCHES, THE FRAME WAS TOO SMALL. I'VE SEEN 15 INCH SEATPOSTS ON THE MODERN FRAMES!!!.THEY ARE DESIGNED FOR ONLY ONE PURPOSE, TO GO DOWNHILL, LIKE A SKIER. LAST THOUGHT ...IF YOU NEVER GO DOWN HILL, WHY BUY A MODERN MOUNTAIN BIKE? GET AN 80'S STUMPJUMPER! LIGHTER MORE VERSATILE. STUMPY CAN GO DOWN HILL TOO ...AND BACK UP again!!

Hey King, can you please ease up on the "ALL CAPS" it makes your posts difficult to read.

Now, if you want a climbing machine, check out Specialized's EPIC. Pair that with a Fox Terralogic fork and you've got a hill climbing monster.

There is always the debate of hardtail vs. fullsuspension for climbing. I think there are pro's and con's of both, but prefer a full suspension for the way down, so I'd chose the FS bike.

The Epic uses incredible suspension technology that only reacts from forces from the ground up, and locks out from rider induced forces. Same with the Fox fork.

Plus, with full suspension, the rear wheel tends to stay on the ground vs. bouncing like a hardtail.

The benefits of a hardtail are the weight savings and the instant feedback.

Try out a 29er. Traction is much better, as you have a longer, narrower contact patch. Also, the angle between axle and point of impact is closer to vertical on larger wheels. This makes rolling up things much easier (down too). The suspension issue is a matter of preference and riding style. You can lose power to a shock on a climb, but you can also lose it to large bumpy things that a shock would absorb.

Good tips above. I'd also like to add that I've found that shorter chainstay length = better climbing. I have an old AlpineStars Al-Mega with super-short chainstays (so short that they had to bend the seat tube around the rear tire) and that thing stuck like glue to any surface.

Tough to find a sort chainstay mountain bike these days. All the hardtails seem to be stuck in the 16.9" range, and the full suspension bikes aren't any better because shorter chainstays usually mean a bit less travel.

Hope to get my AlpineStars back on the trail soon. :)

Good tips above. I'd also like to add that I've found that shorter chainstay length = better climbing. I have an old AlpineStars Al-Mega with super-short chainstays (so short that they had to bend the seat tube around the rear tire) and that thing stuck like glue to any surface.

Tough to find a sort chainstay mountain bike these days. All the hardtails seem to be stuck in the 16.9" range, and the full suspension bikes aren't any better because shorter chainstays usually mean a bit less travel.

Hope to get my AlpineStars back on the trail soon. :)

Fisher's Genesis geometry uses shorter chain stays. I can say from experience they climb quite well.

http://fisherbikes.com/bikes/series.asp?series=genesis