One of the most notable auctions of Autumn 2004 was for Speckles Beanie signed by Bill Gates.
The high bid was £379.
Here is the auction description.

presents

Speckles at the Microsoft Campus in Reading, UK
after his return from the Microsoft Corporation in the USA

The tag is shown unprotected in the photo
but will be carefully protected before mailing

Speckles will be sent in a display case
with a unique CHERISH certificate
especially produced for this unique Beanie Baby

Also included by way of authentication
is the Microsoft compliments slip
enclosed with Speckles
written by the Microsoft employee who kindly arranged
for Speckles to be flown to the USA
to be signed by Mr Gates
and returned to the Microsoft Campus in Reading, UK
(this will be provided without the overprinting in the photograph below)

Biography

"William (Bill) H. Gates is chairman and chief software architect of Microsoft Corporation,
the worldwide leader in software, services and Internet technologies for personal and business computing.

Born on Oct. 28, 1955, Gates grew up in Seattle.
Gates attended public elementary school and the private Lakeside School.
There, he discovered his interest in software and began programming computers at age 13.

In 1973, Gates entered Harvard University as a freshman.
While at Harvard, Gates developed a version of the programming language BASIC for the first microcomputer - the MITS Altair.

In his junior year, Gates left Harvard to devote his energies to Microsoft,
a company he had begun in 1975 with his childhood friend Paul Allen.
Guided by a belief that the computer would be a valuable tool on every office desktop and in every home,
they began developing software for personal computers.
Gates' foresight and his vision for personal computing have been central to the success of Microsoft and the software industry.

Under Gates' leadership, Microsoft's mission has been to continually advance and improve software technology,
and to make it easier, more cost-effective and more enjoyable for people to use computers.

In 1999, Gates wrote Business @ the Speed of Thought,
a book that shows how computer technology can solve business problems in fundamentally new ways.
Gates' previous book, The Road Ahead, published in 1995,
held the No. 1 spot on the New York Times' bestseller list for seven weeks.
Gates has donated the proceeds of both books to non-profit organizations
that support the use of technology in education and skills development.

Philanthropy is also important to Gates.
He and his wife, Melinda, have endowed a foundation with more than $27 billion (as of March 2004)
to support philanthropic initiatives in the areas of global health and learning,
with the hope that in the 21st century, advances in these critical areas will be available for all people.
The Bill and Melinda Gates Foundation has committed more than $3.2 billion to organizations working in global health;
more than $2 billion to improve learning opportunities, including the Gates Library Initiative
to bring computers, Internet Access and training to public libraries
in low-income communities in the United States and Canada;
more than $477 million to community projects in the Pacific Northwest;
and more than $488 million to special projects and annual giving campaigns."

(Quoted from http://www.microsoft.com/billgates/default.asp)