Check and tension your wheels regularly, see Trail Fix - Wheel Truing . There really is no single best solution. See The best bikes in the world for some of our top picks. Most of the coil over oil type shocks are good e.g. rock shocks, Fox, Noleen. Rock shocks and Fox also make some pretty good air shocks e.g. Fox Vanilla.
Riser are better for Free riding, flat for racing.
Flat bars and bar ends are best for climbing, risers are better at descending. Discs if you can afford them, e.g. Hope, Hayes, Magura, Shimano in roughly that order. V's are cheaper, a bit lighter and give good performance though. See How to Mend a Puncture Perfectly Every Time . Or run tubeless tyres at low cost, see Stan's tubeless review .