Best way to mark email for followup

If I send an email to a client and want to remember to follow up, what is the best method?  I use Ceptara in Outlook 2010.

I have tried setting a reminder, but then have to manually file the email and the reminder does not appear as a task when I am planning the next week's schedule.

I have also tried deferring to a task, but find it cumbersome to have a task and an email in the project for the same task.

I find deferring to calendar to be arbitrary, as I never know what my schedule will be, but would use this feature if it had some hidden benefits.

Does anybody have a preferred or different mehtod for following up on emails?

Thanks.