Update: a dual color version is now available: http://www.thingiverse.com/thing:218535

So you have opened your heart for this wonderful person. Now you can show him or her what is inside.
Here is the box to present your Valentines gift in style. The bottom and lid are bonded together so they'll never loose each other.

If you cannot 3d print yourself you can buy a printed version at 3dWeeb's Etsy store (http://www.etsy.com/uk/listing/157663617/heart-box-a-3d-printed-box-perfect-for)

• Update: I made some slight changes to get an easier snap . They are in heartcontainer fdm filmhinge4.stl*

The bottom and lid of this heartshaped box are connected with a filmhinge so you cannot loose the lid. It snaps shut with a little twist.
I made some slight changes to get an easier snap . They are in heartcontainer fdm filmhinge4.stl

This was printed in PLA on a prusa mendel. I am very curious how this will print on other types of 3dprinters so please let me know your results.
the size for printing is 164 x 147 x 33 mm
The closed box is 100 x 100 x 35mm
Sofar I have seen very nice result from makerbots even scale down to 0.6 the hinges work great.

I used Slic3r with concentric infill for bottom,
bottom layer 0,4mm
next layers 0,3mm

To get good filmhinges it will help if you have a concentric first layer infill, have a nicely printed first layer and carefully remove the print from the bed.