I think Nintendo should and will show off their system at E3. To what capacity, who knows, but they're in a sticky position due to the kind of hype they're generating for it. PS3 will be shown, but besides a tech demo or two to show off the power of the Cell, it doesn't really need any game demos since everyone pretty much knows what they're getting: an enhanced Playstation. Xbox 2 will need to show off playable games since its due up at the end of the year. Nintendo on the other hand has promised that the Rev will be revolutionary, and will thus need to prove how and why it is. Whether this needs to be done with actual hands-on play remains to be seen, which looks to be the main point of debate here. If showing playable games will overextend what Ninty is capable of showing off then they shouldn't, but if it's necessary to show off what's revolutionary about the Rev, then they should.