Depends how you define failure...
There are those that had the market in their hands and let it go:
Wordperfect
Lotus 1-2-3
Sony Betamax
Kodak
MSN Messenger
Compuserve
Myspace
Friends Reunited
There are those which just died of old age:
Ceefax/Oracle
Prestel
Fax
There are those products which are just plain shocking or badly managed:
Windows ME
Xbox 360
Nokia Ngage
Windows Pen
OnDigital
Lotus Notes
Every mobile platform from Microsoft apart from Windows Mobile 7
Google Wave
IBM OS/2
Microsoft Zune
Amazon Fire Phone
There are those which sounded like a good idea but the market had moved on:
Blu-Ray
Minidisk
Iomega Zipdisk
There are those products which were innovative but were too ahead of their time or weren't good enough:
Apple Newton
Microsoft Band
Sinclair C5