I've been using tupperware as project enclosures for many of my projects, and they have many advantages:
-They are normally cheaper than conventional project boxes.
-They are found in almost any store, or in the kitchen.
-They seal better.( if you need that feature).
-They are easier to drill or cut.
-They are more flexible so they don't crack when drilling or cutting.
-You can access the inside really quick.
-They look really cool with all the electronics showing.
Some of you already use the tupperware to enclose your projects, here are a few examples:
Solar LED bike bag
Tuperware iPod Boombox
Computer Speaker Conversion
Embed an OEM GPS Into Anything
Garden Pests Detecter
Self-watering, Self-regulating Container Garden
Simple "toss lamp"
Thank you for reading, have fun "tupperwaring"!