you mean for digital audio? you probably want protools. if you don't want to use digidesign hardware, logic is quite good but not so easy to use. there are other options; those are the two high-end options you'll see in studios.
Another option for a solid, more mid-range program is BIAS Peak.
It is a nice, fast, program that is pretty tight. The full feature version comes with some very nice batch processing features which I find very handy (one automatically creates files from Markers).
They have a limited edition version, starting at $99, without some of the batch features.