I certainly understand the frustration that can come from the inappropriate use of the caps lock, but disabling the caps lock key is a little like taking away a NASCAR driver's ability to make right turns. Sure, the driver doesn't need to make right turns very often, but can you image the predicaments that could occur in the pit area if drivers no longer had the ability to turn right.
Personally, I frequently use the caps lock; and not simply to approximate Austin Powers telling us how he has, "LOST THE ABILITY TO CONTROL THE VOLUMN..." of his voice.
For instance, when I am writing SQL statements, or even typing the word SQL or MySQL, it is fairly common for me to use the caps lock key. While MySQL does not require that reserved words be in caps, I generally like to do so out of convention and for debugging purposes. For instance
SELECT * FROM somedb WHERE id = 42;
is slightly more readable than
select * from somedb where id = 42;
This is a fairly simplistic example, but image a more complex SQL statement and attempting to hold the shift key for every letter of a reserved word that you intend to capitalize. I find that to be a bit awkward.