Well, the question you are asking is difficult to answer since it can be different cameras to different people. Its very preferencial.
For people who shoot Nikon, some would say the Nikon F6, a top of the line professional camera. But that camera will set you back a lot.
I dont know what Canon's top of the line model is, but people who shoot Canon would argue its theirs.
Those are but two of the companies who make 35mm SLR's out there. But since digital is becoming more and more popular, there are great deals out there on 35mm cameras and kits.
I would suggest buying a camera that has the options and things you are looking for in a camera, and what suits the needs of what you shoot.