Here are some sites that have collected the 'best' web applications for students.
1) Web 2.0 Backpack: Web Apps for Students
http://www.readwriteweb.com/archives/web_20_backpack_web_apps_for_students.php
2) Back to School: 10 Great Web Apps for College Students
http://www.readwriteweb.com/archives/top_10_web_apps_for_students.php
3) Best Web Apps for Education
http://larryferlazzo.edublogs.org/2008/09/11/the-best-web-20-applications-for-education-2008/
4) Best Home Page Creators
http://larryferlazzo.edublogs.org/2008/11/26/the-best-personal-home-page-creators/
5) WebHeads - PageFlakes BLOG
http://www.pageflakes.com/webheadsblogs/23366834
