Well, a lot of us assume that there is going to be some kind of GameCube bundle when the new Zelda game comes out... Even though most of us already have a GameCube, is there anything Nintendo could do to enrourage you to purchase a Zelda Bundle?
While it's a long shot, if they released the new Zelda game with a specially decorated GCN (and whatever pre-order bonus you're supposed to get with the game) for $100, I'd probably splurge and pick up the second GCN I've been wanting.
Second, I'd love to see a Deluxe Zelda Bundle, including a special GCN, Wind Waker, Four Swords Adventures, The Zelda Collection Disc, (perhaps a GCN-GBA cable) and, of course, Twilight Princess all for around $200. I think this might encourage some of those who passed on a GCN and Wind Waker before into playing (and enjoying) Wind Waker and FSA when they get their GCN for Twilight Princess (and we all know they're going to get a GCN and TP...) $200 seems to be a decent price for the bundle - Right now you can get the GCN with a $30 game for $100. $70 GCN + $30 FSA + $20 WW + $50 TP + $20 Collection Disc + $10 Link Cable = $200! Sweet!