[woodguy]

Call.

I think the naked A [img]/images/graemlins/spade.gif[/img] does this enough to make it a call.

If he missed getting chips from you with the nut flush on the turn, they usually bet the river to get some value.

If he's ballsy enough to check twice with the nut flush, good for him, make a note.

I doubt he does this a non-nut flush or straight.

Nuts or nothing....probably nothing.

Regards,
Woodguy