Forgotten Attachment Detector plugs into Outlook and offers exactly what I've been looking for: Flexible settings that scan your e-mail for a variety of terms (like "find attached," "have attached," "see attached," and others) rather than one catch-all keyword like "attached." The program is preconfigured with a slew of smart attachment-related keywords, but you can add your own, allowing you to truly personalize the program to your particular e-mail style.
The program also checks what it calls "secondary keywords," like "attaching" and "enclosing." These secondary terms won't sound the alarm unless accompanied by a neighboring term like "doc" or "file." These terms, too, are fully configurable. Think it's all needlessly complicated for a utility that simply warns you about forgotten attachments? Not at all. This app elegantly avoids false positives, which would otherwise lead you to turn it off out of sheer annoyance.
And last but not least, Forgotten Attachment Detector also (optionally) warns you if you try to send the message with a blank subject line.
Maybe I need to get out more. [via Digital Inspiration]