I don't like this question which says:
Is there a bike, which contains all the qualities in one?
Like, uphill, downhill, speed, road, trailer, lightweight, heavy duty, tough.
Instead of having a debate in comments on the main site, I thought we'd be better off here on Meta.
The only possible answer to this question is "no", and that is obvious. No one will benefit from that question-and-answer.
I don't believe the person asking this question was really curious. They may wish for an all-in-one bike, or their domestic partner may wish they only had one bike, but they don't really wonder whether such a beast exists, or maybe they're just fishing for reputation points.
The question is quite vague.
For contrast, here are some more specific questions, that might actually be useful to someone:
"how can I set up my road bike so I can safely ride it down a steep dirt path?" (since I want to spontaneously ride somewhere that looks fun)
"how can I set up my mountain bike to be more efficient on the road" (since I ride on the road to get to my favorite off-road area)
"how can I set up a bike to work equally well for up-hill and down-hill off-road?"
"How can I set up my bike to be as fast as possible on my commute to work?" (because I'm a speed demon and my only chance to ride is while commuting)
fishing for reputation pointand even more surprising was that judging that I was not curious. That was very rude, my intensions of asking that question was to know if I could get a bicycle that was capable of doing everything that I throw at it, whether its racing, riding up hill, down hill, cross-country or pull few tricks. A bike which is heavy duty, super light, better traction, ergonomic, aerodynamic. – Starx Jan 18 '11 at 8:28hybrid-bikesimply. Please review the question. – Starx Oct 1 '12 at 4:08