there are literally hundreds of choices when it comes to downhill bikes dude, what sorta budget you got? second hand or brand new?
downhill bikes are very good at one thing only that is going downhill going back up really isnt on the menu so if you are thinking about dabbling in a bit of downhill and then having a punt around the local woods or trail centres you'd be much better going for an alpine based bike i used to have a downhill bike and now have a alpine bike and i can the alpine bike is a million times better unless your going to be serious about riding downhill then id go for a lighter more pedalable bike, just my opionion though mate