Acid Pro 4 is also a gas. PC only, though. I find it pitch and time shifts better than Live, though most of the film composers I know use Live...Acid also has a particularly fine collection of "Acid-ized" samples, which can be manipulated in a billion ways without even plugging in a keyboard. Also X-Phraze. Similar to Live and Acid. If you use a PC I'd go Acid. Live will read the Acid sample library, but the samples dont seem to interface quite as well when you open them in Live.

my 2 cents.