I've seen some of the Blue AV edition iMac (or whatever they're called) with screen burn in. If you have a white-enough (or light-enough area) without movement it is possible.
A+ Core Hardware, Software Certified (May 13 2005)
the new beast...
AMD Athlon XP 3200+ Barton running at 2.16 Ghz.
GeForce MX 4000 (mainly takes the load off the main system)
Creative Labs Audigy 24-bit sound.
Some Case from tigerdirect
512 MB Ultra DDR RAM.
80GB Seagate HDD
LiteOn CD-RW / DVD ROM drive.
currently looking at a litescribe drive at staples, due to its ability to label the CD shortly after being burned.