Ok, if my seller ships fast, i will be the proud owner of a Gamecube this week.
I couldnt wait and got RE 1 and ZERO and ZELDA Wind Waker allready.

Anyway, i see there are 4 different ModChips for the cube out there:

Xeno Modchip
Qoob SX
Qoob Pro
Viper Extreme

And if i would make some backups, would i have to use Mini DVDs to back up onto ?
If so, i wouldnt need a chip capable booting big DVDs.
Now which Chip do you recommend ?

Media size is irellevant with regards to the chip you choose, it depends on your wants. Mini media is nothing but aesthetics, normal size media is cheaper and far more plentiful.
You should choose a chip based on your needs for making backups, and software useage.

Do you want to be able to make your own backups and you have a BBA? All chips are a viable solution here, but the XenoGC isn't your best choice in this case just for ease of use.
If no BBA, the Viper Extreme is your only option.

If you don't want to be able to make backups, go with anything BUT the Viper. Theres no sense spending the extra money.

Homebrew and emulators etc are your thing? The Qoob Pro or Viper Extreme have 16mbit flash where you can store these rather than burning a DVD for everything all the time.

If you don't care about anything but playing backups and none of the rest apply, get a XenoGC or Qoob SX. The XenoGC is probably cheaper than the SX (I'm not sure of pricing at this point, I bought my Qoob Pro quite awhile ago), but the XenoGC isn't simple to load homebrew and not all works with it.........so unless you ONLY want to play backups go with an SX.

So to sum it up i can make backups of my original GC discs on my PC (like with CloneCD) burn em on a Mini DVDR and boot them up with any of the chips ?
I thought GC discs couldnt be read by PC ?

It cant, basically you get your Gamecube, With BBA, and hook it up to your computer, and your computer uses the gamecube as a disc drive pretty much and you copy the games like that

Then you can burn the games to MiniDVD (i reccoment the 4X Ritek btw) or just play them off your HDD through the BBA

Hmm so i need the more expensive chip and an extra BBA.
I will think about that again. Its quite a hassle this way

ok so i thought about this a while.
Qoob Pro is 40 Euro atm. Price dropped a few days ago. Yet i need a BBA to make backups with the woob pro. The BBA costs some euros too.
The Viper Extreme is 50 Euro. I need no BBA. So the Viper Extreme is cheaper in the end, considered i want to make backups of my games.

But i have 2 questions left:
I read the Qoob supports direct boot ? Do i need to swap discs with the Viper Extreme ? Didnt find any info about this.

Can i stream ISOs to the GC with the Viper Extreme over USB as i would be able to stream em with the BBA and the qoob ? Or is USB too slow ?