This is basically a re-post of the one from the old forum. However, I added or changed some stuff here (marked as italicized text).
The list is still incomplete, and that's because I have to test out keys from the other builds and see if it works with the build that is currently used (e.g. using the build 2419 key for 2542). There are indeed some keys that are interchangeable, which means that some of the builds have the same key algorithm.

I actually noticed this when I went to a site that posts a product key for build 2419. The one from the old thread is RBDC9-VTRC8-D7972-J97JY-PRVMG, but the one from this site is DW3CF-D7KYR-KMR6C-3X7FX-T8CVM (which was mentioned as the key for build 2458 in the old thread). When I tested them, both work fine. This leads to some more curiosity of using some more Whistler keys and see if it works on different builds too.

Now recently, I decided to install build 2542, which is only a build before 2600. Now, instead of using the suggested key from The Collection Book, which is BX6HT-MDJKW-H2J4X-BX67W-TVVFG, I used the one from 2419 instead (RBDC9-VTRC8-D7972-J97JY-PRVMG), and it also works.

I added all of the three keys below, and you can have some little fun trying all the product keys! :P

All BIOS dates are in DD/MM/YYYY format.

2202: 02/03/2000
2211: 03/10/2000
2223: 04/12/2000
2250: 06/29/2000
2257: 08/11/2000
2267: 09/11/2000
2276: 09/29/2000
2287: 10/13/2000
2296: 10/25/2000
2410: 12/09/2000 F6PGG-4YYDJ-3FF3T-R328P-3BXTG
2416: 01/05/2000
2419: 01/14/2001 RBDC9-VTRC8-D7972-J97JY-PRVMG, DW3CF-D7KYR-KMR6C-3X7FX-T8CVM, or BX6HT-MDJKW-H2J4X-BX67W-TVVFG (all keys work, so pick one of them)
2428: 01/30/2001 DTWB2-VX8WY-FG8R3-X696T-66Y46 Every build has the same product key until 2454
2430: 01/31/2001
2433: 02/07/2001
2446: 02/25/2001
2454: 03/07/2001
2457: 03/10/2001
2458: 03/10/2001 Same as 2419
2462: 03/16/2001. Personal/Home Edition: Same as 2428, Professional: Same as 2419
2463: 03/29/2001. Personal/Home Edition: Same as 2428, Professional: Same as 2419
2465: 04/13/2001. Personal/Home Edition: Same as 2428, Professional: Same as 2419
2535: 04/08/2001. Personal/Home Edition: Same as 2428, Professional: Same as 2419
2542: 12/08/2001. Personal/Home Edition: Same as 2428, Professional: Same as 2419