Macos debugger

[QuakeGamer]

Hopper with GDB is probably the best you can get. You might also simply use pure GDB which is very powerful, but is harder to get used to. But if you are searching for something like SoftIce, its the nearest you can get.

You might also try using XCode + GDB - tho i never tried that.

Edit:
There are front-ends for GDB aswell, such as DDD. You might have a look at those too.