A few months ago I passed my desktop to my wife because her machine was too slow for what she needed to do. I then took a machine that was slower (1.8 v 2.4 GHz) and had less memory (768 MB v 1 GB), and installed Ubuntu for my own desktop. In general, my machine accomplishes tasks faster.
The one annoyance with Ubuntu is that Audacity, which is my sound software of choice for preparing my podcast, works very poorly with PulseAudio. I use Audacity for Windows under Wine, and still occasionally have to restart the machine just before an audio editing session.
I know there are other solutions, but that is the editor that works best for me. Given time, one hopes this will improve as well.