Manual Note: Manual hole note creation is definitely an option if you are only doing this once or twice. But that is painful if you are doing it often.
Custom Hole Feature: You can cheat and create your ownstandard hole table for straight holes and specify the note layout. Limitations:
<LI>You can only use this with through holes because blind holes don't allow you to turn off the thread surface.</LI>
<LI>You have to toggle off the thread surface manually.</LI>
<LI>You have to know the hole sizes you want to create and add them to the table because you cannot use a diameter that doesn't exist in the table. http://www.ptc.com/cs/tpi/107248.htm</LI>
UDF: You can create a straight hole and add a feature level note to it. Then you can create a User Defined Feature for that hole and just place the UDF when you need it. The drawback is UDFs can only be placed according to how they were created. Thus if you create it as a linear hole, it can only be placed using linear references.
Custom Code:The last option I can think of is to use J-Link or some other API to force the creation of a note for a straight hole.