Is a CD RW good enough to back up my computer or do I need a USB?

You pays your money and takes your choice ..

1) CD / DVD's don't last for ever - CD's / DVD's are 'written' from the hub outwards .. and when they 'fade' in sunlight, the 'rust' gets in from the outside edge ... so if you don't fill them up totally you have a better chance of getting data back = even so, you need to replace them (copy to a new disc) every couple of years to be sure ... (I have some CD's that are 5 years old and no longer 'read' all the way to the edge :-) )

2) All hard drives will eventually fail. If you use a single drive as a back-up, sooner of later you will loose the lot.

If you use an external RAID (mirror) and ALWAYS replace BOTH drives in the pair with the 'current best buy' every time you run out of space (or every time one of the pair fails), then your RAID (and thus your data) can last for ever ....

quick answer - USB.

CD RW are fine it you have a few files you want to backup, but when you start getting into the realms of 100's or 1000's of file or the whole computer - then USB is the way to go.

With CD's or DVD's there are a real pain when you want to add just one more file or even want to delete a file thats not required any more, plus the fact that a CD/DVD can easily be scratched and then you can't get back to your data anyway.

Have a look at http://www.pool-king.com/depositit.html for details of an online backup solution which works exceedingly well and the best bit is you don't need to remember to back it up as it does it all for you!

I use http://www.my100gigs.com/ because CD RWs and USBs are unreliable. But if your careful with the disk CD RW is almost as good. USBs can just stop working without any notice, they are ok for keeping files on hand but no good as a backup (break easier than your hard drive).

It all depends, I prefer a DVD+RW, first of all because you can put up to 4.7Gb material in it, and CD however can only put 700Mb, and a USB memory stick can put up to 64Gb depending which memory sitck you have, some of them can only put inside just 1Gb, usually the portable hard drives are like normal hard drives, except for the fact they are not connected directly to the motherboard, but they are connected through USB and take it wherever you want.

So conclusion...Memory stick of at least 8Gb for not much of a stress or a DVD+RW.