Excel is really an extremely powerful tool and is very appropriate for the product backlog (and it has my preference if suitable: just share the product backlog on a network drive and there you go). I have used the following templates successfully in the past:
- Henrik Kniberg’s Index Card Generator and a wall for the sprint backlog
- Petri Heiramo’s advanced product and sprint backlog template (video tutorial here)
You can browse my personal collection for more of them but I recommend the two above.