DVD would be possible, CD not. Because the Wii's drive cannot read CDs. Its a hardware limitation, completely impossible. And on DVDs, you still have to launch a homebrew first, so you have to start HBC, then run the homebrew, then put in the disc, then run the actual homebrew you want. So you still need an SD card, and it takes much more effort. Its much easier just to have everything on the SD card.
And as for internet, there is no homebrew internet browser. There is the official Internet Channel which you have to pay for, or you could use one of the Wii Linux distros, if you have wired internet (You need the USB LAN adapter, Linux doesn't work with WiFi on the Wii yet), and then run firefox or something. But you need wired internet, and I think it still isn't great. You're best to get the official Internet Channel, or wait on one of the two homebrew internet browsers that are being made.
Sorry if I confused you at any point, if you need anything explained in more detail give me a shout.