Thanks for the reply but I am a little confused. How would partitioning my drive be counter to my purposes? In my view, the only way to back up 2 different sources onto the same drive is by using different partitions? Indeed FAT32 is a solution in theory but there are some drawbacks. First of all it is not the most efficient usage of disk space given the cluster size of NTFS is different than FAT32. So my 120GB partition on my external HD would be more full than my 120GB NTFS internal partition. More importantly, however, Apple's HFS+ allows for more freedom in filenames than windows. Most of the "illegal" characters not allowed in Windows are valid in HFS+. I worry that backing up my entire Apple HD onto a FAT32 drive would bring up the possibility of errors such as these, possibly rendering any backup useless.
Disk imaging software does exist for OS X, and in fact the free offerings (CarbonCopyCloner is most popular I think) are very good and for my purposes will be sufficient. It is on windows that I need suggestions for backup software.
Lastly I'm a little confused about the DVD backups? In my eyes, optical media such as DVDs or CDR would be the less stable medium? I have been backing up to hard disks for years, and even have data on hard disks that are down in the 200MB capacity range, and have never had a problem. Also factor in that this external drive spends the vast majority of its life inactive and not plugged in, I feel that the stability of the hard drive (both data-wise and mechanically) are nothing I need to worry about.
I admit I have not followed recordable technology very closely lately and my opinions were largely formed in the early days of CDR. Are optical media more stable now? However even DVD backing up is not a very practical solution for me at the moment. Currently my XP hard disk has about 60GB on it, which would be a major pain to back up on to optical media. In the past I have used internal hard disks as backups (and had them repay me ten times back when I had to make use of them!) but I can't install a second HD into my laptop and my XP PC is a Shuttle mini-case with no 2nd HD in it. So this time I opted for an external drive as a backup. I should mention, however, that I also run periodic (i.e. bi-weekly or so) backups of my documents and other important files onto my iPod, so really I will have 3 copies of the most critical data floating around at all times.
Again thanks for the help, but I think I am confused about the suggestions you offered?
Ruahrc