The right tire for you, might be different than the right tire for me. It comes down to your local terrain, and your riding style.
IMO there are four things to think about when choosing a mtb tire.
1) Width - a wider tire 2.4+ will be heavier, but will give you a larger foot print on the trail.
2) Tread pattern - bigger nobs will be less efficient, but will have more traction. In addition to the size of the nobs, is the size of the gaps between the nobs. A tire like a DHF/DHR has big knobs that will grip well, but they may feel sluggish when you pedal. Tires like the Assegai and the Aggressor have more tightly spaced knobs, and will have lots of traction while rolling a little bit more efficiently.
3) You don't need to have matching tires front a rear. That goes for tire width and tread. You can run a 2.6 in the front and 2.4 in the rear. Or an aggressive front tire like a Assegai in the front, and a Recon in the rear.
4) Tire casing - Downhill and enduro tires will be tougher with more resilient sidewalls - but they are heavier. XC tires will weigh much less, but be less resilient to sidewall cuts from rocks.