Of course, you can do everything with one partition. What I didn't tell you however, is the amount of data, I'm juggling - one of my main applications is video editing. Just yesterday I added another 250 GB HDD, so now I have 820 GB.
Maybe it's just emotional, but I do like to have my data clearly separated from all the incredible rubbish Win XP and every other installed application are adding to my disk. Not sure if anyone else is understanding all that stuff - I'm definitely not. (Ironically: what I hate is Microsoft's view: "your computer is all ours, but well ... here's a tiny directory called 'MyFiles' where you can play around if you really need to". My view is the oldfashioned "I payed for this PC, so it's mine - if all that other stuff really needs disc space, well, then I'd give them one directory 'System' where they all can hide"). As I said, simply emotional - I know that these are not hard arguments at all.
But today I just learned a real hard argument for separating system and data into dedicated partitions. I was playing around with XPprof's backup program and found out that if you want to backup the system drive with the option of system recovery (using that nice floppy Backup generates), than you have to backup the entire partition - 820 GB (if that were all on one sinle HDD). No option left to select a subset of that data.
Concerning PartionMagic - it all worked perfectly with FAT, I really loved it. But with NTFS it's a nightmare. Maybe that's due to the large partitions I have (the big one for video footage is 500 GB !), Partition Magic 7.0 specifies up to 60GB or so, but I definitely had trouble with partitions as small as 10GB or less. And others had too.
That's why I'm looking for a tiny little tool for moving and reseizing...