Rated 5 out of 5 stars
I love this application. I've been waiting for something like it for years, and have always wondered why a sound selection wasn't included in Thunderbird filter function.
When I'm busy, it's great being able to ignore emails except for those sent by specific recipients. It's like have talking Caller I.D.
Additionally, you can use it at night and set it to only make a sound when emergency emails come in or those from specific senders (e.g., your children, spouse, etc.).
What neostart (another reviewer) mentions about the default sound is true but easily addressed. After creating the ToneQuilla filter(s), simply turn off the default sound and create another ToneQuilla filter that's the opposite of the other(s).
For instance, let's say you want to be alerted when your children email you. Create a filter based on your kids' names (e.g., Sender matches Son's Name and Sender matches Daughter's Name). Then create another filter that's the opposite (e.g., Sender does NOT match Son's Name and Sender does NOT match Daughter's Name). The first filter would have the unique sound selected for your kids (or any others from whom you always want to hear), while the second filter might be associated with the default sound.
The above mentioned technique not only solves the problem that neostart cited, on the top of that, one then has the ability to easily toggle an unlimited number of filters simply using Thunderbird's Message Filter window. I find this comes in handy since I have different preferences depending on the time of day or night.