this is a "to each their own" comment.
When I organized my installation I too initially made a separate drive for
apps and the system. Then I realized that it really provided no benefit and
I cannot really backup the system drive and restore it cleanly without the
application stuff being there as well. I.e. it would be a muddle if I tried
restoring the system drive without the installed apps (which were on a
separate drive) which had their hooks placed in and about the sys image (e.g
registry); if I want to backup/restore the apps installation anyway then why
not put them in with the system.
The only key item for me now is to keep that which I consider "data" in its
own separate drive so that it can be backed up easily.
So, had I 200GB to play with....
C: SYSTEM & APPS
15GB
UNFORMATTED
5GB
D: BASIC DATA - i.e. normal saved files from apps, downloads, etc
30GB
UNFORMATTED
30GB
E: MASS DATA - i.e. mp3s perhaps.
60GB
F: MISC - play area - you never know when you want some space to muck about
in. 10GB
T: TEMP
10GB
The unformatted areas are there to 1. reduce the time it takes to format
initially, and 2. leave space at various places in the drive to exapand a
partition as needed without moving more than is necessary.
If you want to backup to HD, I suggest buying a 2nd drive of whatever size
you need and backup to it.
ps. Make sure you have a copy of PartitionMagic! It's the most useful
utility I have ever come across.
Hope this is useful
Unc