Hardtails, the perfect mountain bike for a beginner although, there are hardtail mountain bikes for more advanced riders.

many manufacturers offer recreational mountain bikes one of my favourites is the Norco Scrambler it features :

SR XCT V2 with 100mm of travel.

Tektro IO Mech disc 160mm.

Shimano Altus Rear derailleur.

for full specs on this bike visit

http://www.norco.com/bikes/mountain/adventure/scrambler/