GC doesn't have a DVD drive, but it uses a special CD drive instead (1.5gig capacity? or something like that)
Not
entirely correct. Gamecube
does have a DVD drive... it's just only big enough to hold 3 inch DVDs (1.5 gig). Since normal-sized DVDs cannot fit in it, obviously you cannot use it as a DVD player.
Advantages to the smaller DVDs: Well, they're harder to burn (I've never seen 3-inch DVD-Rs on sale) so this has killed piracy of GCN games, at least for now. It's also just... smaller. Not to mention that the track that the actual data is on is only like an inch wide, meaning extremely low seek time (which probably contributes to GCN's amazingly fast loading speeds).
Disadvantages... well you can't hold as much data (1.5 gig compared to DVD 4.7 gig) but 1.5 gig is still plenty for most games. They can always go double-disc or double-layer or maybe even double-sided (or some combination of the three). And of course, you can't use your GCN as a DVD player :-p Some people care about that, but I don't.
If you REALLY wanna use your GCN as a DVD player, you can buy that thing from Panasonic (Q-something) that is a DVD player Gamecube combo. Unfortunatly, you have to get it modded to play US/Europe DVDs/games (I dunno if it'll do PAL, actually) and it ends up costing like $400. Ow.
Hopefully they'll be smart and release a US version.
Interesting thought... I wonder if the GCN can read 3 inch CD-Rs? I've seen them at stores. Would be kinda interesting, b/c then it would be possible for the average user to program for the GCN (like some people have come up with Game Boy or PSX demos).