You need to be careful dropping apparently unused indexes. This is from today's newsletter from Brent Ozar:

Unused indexes are tricky. When you are analyzing this data, you have to keep in mind that this data is only available since the last restart. If you rebooted the server yesterday and are viewing the data today, you might see a lot of unused indexes in the list. But are they really unused? Or have the indexes not just been used YET? This is a very important point when deciding to disable or drop an index based on this list. If you reboot your servers monthly due to Microsoft security patches, consider reviewing the list the day prior to the reboot. I once dropped an index 3 weeks after the server was rebooted, thinking that the entire application workload must have been run by now. A few days later, I got a call on the weekend that the database server was pegged at 100% CPU utilization. I reviewed which queries were using the most CPU and found that the top query’s WHERE clause matched the index I had dropped. That query only ran once a month, which is why it hadn’t recorded any reads yet. We later moved that monthly process to another server that was refreshed regularly with production data.