Everytime someone brings up the two (DOL-001 and DOL-101) models of the GameCube, all they ever mention is the removal of the Digital AV Out port in the newer model as if that is the only difference.
The newer model of the GameCube contains several differences, though they aren't immedietly obvious unless you look around. Much like Nintendo's other systems (such as the Top Loader NES), some of the differences are to reduce manufacturing costs and others to make minor improvements to the hardware.
This is the most well-known and obvious difference between the two models. The newer model doesn't have that port, so Component cables can't be connected. That means Progressive Scan is not available with the newer model.
Nintendo is known to include unused ports on their systems that are removed later on. The GameCube's Serial Port 2 is unused, there is nothing available to make use of it. The port is removed from the newer model.
On the original model, the nameplate can be removed. There are two tabs on the bottom of the disc cover, just below the nameplate. The disc cover on the newer model doesn't have those tabs, so the nameplate normally isn't removable.
The DOL-101 model contains firmware, which prevents most discs from Datel from working. These include Action Replay versions 1.06 through version 1.14b, Ultimate Codes, and Freeloader versions 1.04 and 1.06b. Instead, an error message appears. Pictured above are Action Replay version 1.14b and Freeloader version 1.06b inside the DOL-101 GC.
One complaint some people have about the original models, is its tendency to incorrectly read a disc and display an error message. I haven't run into any major problems with my original GameCube, but others have and shortly after the console's launch Nintendo even provided repairs for free. The newer model works around this issue by having a newer, more advanced laser that correctly reads discs with fewer errors. However, the lasers in the newer models apparently don't last as long as the one in the original models.
Not a hardware difference, but oh well. The AC Adapter that comes with the original model (left) is 46 Watts, while the AC Adapter that comes with the newer model (right) is 48 Watts.
These are the same two pictures as at the top of the page. They show another, minor difference with Platinum GameCube's of the newer model. DOL-001 Platinum GameCube's are colored entirely Platinum, just like how GameCube's of other colors are just one color. However, the rear of Platinum GameCube's of the newer DOL-101 model is black. I don't know what Nintendo's reasoning for doing that is. The Indigo, Jet black, and Spice orange GameCube's of the newer model are just one color, just like the original model. But the rear of Platinum GameCube's of the newer model, for whatever reason, is black.