Expensive but worth it
Pitch 'n Time is one of the smoothest sounding time compression plug-ins I have ever heard. Serato is DEFINITELY one of the leaders in functional pitch and time manipulation. It's independent time and pitch sliders are easy to use, the ability to draw in a pitch and/or time curve is highly useful and I have yet find a more superior plug-in in its class. I use it every day for everything from subtle time correction on a voice-over to completely whacking a sound out for sound design. This is high on my list of "must haves."