Thanks for your replies everyone.
As I suspected HDs don't really need toys because we have our imaginations!
However...
This one looks nice and discrete and probably would be good for the sort of all-over use I have in mind. http://www.goodvibes.com/cgi-bin/sgin0102.exe?FNM=53&T1=1+2+AH+0503&UID=2005062904282382&UREQA=5&UREQB=4&UREQC=3&TRAN85=N
I think I will wait for a good oportunity when the mood is right and tell her that I'm going to buy her one. Remember the SuperDave rule #1. Don't ask for things - tell him/her what you are going to do.
Example:
"Can I buy you a lovely tingly vibrator?". Expected LD answer - "NO WAY!"
or
"I'm going to buy you a lovely tingly vibrator!". Expected LD answer "No way! (thinks - ohh I hope he has it by next Friday!)"
See what I mean?
Love to you all, SD