TCP/IP Protocol Suite, Second Edition by Behrouz A. Forouzan, McGraw-Hill, ISBN 0-07-246060-1 (ISBN 0-07-119962-4 for the paperback version). The Kårbokhandel has this book in stock (650:- paperback version, Nov 2004). This book is also used by IMIT's Internetworking course for example. The book has a good coverage of modern Internetworking topics and has a very pedagogical top-down approach. In the details, however, it has several annoying errors - it is not a book for hands-on experiments.
TCP/IP Illustrated, Volume 1: The Protocols by W. Richard Stevens, Addison-Wesley, 1994, ISBN 0-201-63346-9. This used to be the "bible" of internetworking. It has a bottom-up approach and is fantastic in its details. Large parts of the text of the book is the same as the RFCs, which means that by definition the text is correct. If you want hands-on experience, this is the book for you. The drawback is primarily that the book is old (it does not cover NAT, firewalls, VPN, IPv6, etc), and Stevens is unfortunately deceased, so there will be no new versions. It might also be somewhat expensive.
An alternative to Forouzan is Internetworking with TCP/IP: Principles, Protocols, and Architectures, by Douglas E. Comer, Prentice Hall, 4th edt. 2000, ISBN 0-13-018380-6. It also uses a top-down approach but little detail, but is usually more correct than Forouzan.
An excellent book used in many other universities is Computer Networking; A top-down approach featuring the Internet by James F. Kurose and Keith W. Ross, Addison-Wesley, 2003, ISBN 0-321-17644-8. It is modern and accurate and might be the best choice.