Well, just to be clear, I'd like to point out 
that just because someone is willing to pay more 
than you would have been willing to, doesn't mean 
they want it more than you do.  People have 
different means after all and different sense of 
what they believe is a livable price.  However, 
you might have other reasons/feelings for 
believing this person wants the item more than 
you do. 

You still are pretty attached to the item 
though.  Unless the person is close to me, I 
usually let my own attachment to the item decide 
whether I will sell/trade or not.  I don't try to 
compare my want for the item with the other 
person's absolutely.  There's no way to tell for 
sure.  (Also, while this probably doesn't apply 
to your cases... I've seen some situations where 
a person has acted as if the other item was an 
absolute dream... but the dream faded quickly 
after they got the item and they ended up 
selling.)

I would give the offer due consideration, but if 
I really didn't want to sell it, I wouldn't.  I 
have traded/sold things in the past to friends 
who I felt 'wanted' them more... but because they 
were my close friends and I knew them and knew 
how much they wanted it, I -wanted- to sell it to 
them. 

Keys