Will you install software on the same partition as Windows system?
Solution 1:
I'm going to completely contradict the other answers posted so far, as I don't believe splitting data/apps/OS between different partitions is really beneficial.
If you have a good backup strategy (you do take backups don't you?), then there really is no need. Windows 7 (and the same applies to other versions of Windows, Mac OS X or Linux), provide you with a directory structure for user data which is perfectly suited to storing all your music, video, office docs, etc. By design it provides security (i.e. you can keep your data private from other users), but you can also share data between other users if you prefer.
As the other answers state, you might have to re-install windows, every now and again because it goes pear shaped, but if this happens, why not just restore from your most recent backup? You state you are running Windows 7, and if you are using the native backup tools, your backup will include the OS, apps and data. So a restore will take care of everything.
I wouldn't be happy reinstalling Windows on a disk that contained data I cared about, even if the data was on another partition, and what is to say that if your OS is hosed, that your data can be trusted anyway e.g. if you suffer a virus infection or a system compromise, then can you really trust your data and only reinstall the OS?
The other drawback to splitting partitions between data, apps and OS, is that you have to guess what size to allocated to each. When one fills up and others are empty, you will regret doing this.
On the contrary however, if you are looking for ultimate performance, I would install the OS on a fast SSD disk, and keep my data on a cheaper conventional disk, however you suggested in a comment that you have a laptop, so this probably isn't an option for you.
Solution 2:
I keep my data and software separate if I can, but I don't see any issue with installing software on the same partition as Windows. In fact, this is usually preferred because some software makes assumptions that it is on the same drive as Windows anyway.
As for your question about provisioning space, go with at least 100GB for Windows and the software if you can do it, and then the other 220GB (or more, depending on your drive size) for data.
Bear in mind the only reason for logically partitioning a single physical drive is to have your data separate from Windows if it crashes. However, if the drive fails, the partition serves no real purpose. Something to think about.
In the end, I propose the following solution for you:
- Install Windows
- Install your software
- Get everything up to date
- Do a full drive image (Windows 7 backup will do this)
- Keep your data on a separate physical drive
- Make regular backups on a separate drive
If anything ever goes wrong with your Windows drive, you restore from backup(s), either the image and your standard backups, or both.
Solution 3:
There are several good, reasonable and logical reasons for splitting Windows installs onto multiple partitions, separating Windows from apps, or more commonly, Windows + apps from end-user data. These may include ease of setting up data-only backups, faster recovery from hard drive error, and ease of managing multiple operating systems on one machine.
But, in my experience, the typical end-user will someday get burnt by this, as they run out of space on the Windows partition after adding yet another app, or downloading yet another Windows theme. At they approach this point, their computer will begin to slow, as Windows reduces its virtual memory use to accomodate its expanding girth. When they eventually get there -- and they will -- they'll need help, perhaps urgently, and help may not be close by.
This sort of partitioning is unfortunately on the rise, as people consider configuring their systems to boot off expensive-but-fast SSDs.
Solution 4:
If you're using two drives at all, you're using symlinks. Some of them will be more difficult than others (the coding ones probably), but 20 isn't much more than 2.
The main reason to split is because Windows is on an SSD, or because you want to frequently reinstall Windows but not the programs. SSDs are now cheap enough to buy something big enough for the programs as well, and while reinstalling Windows will solve a ton of problems, there can still be a lot of problems left in the programs. Data is different, but not that different, it can still house problems.
To sum up, make sure you're doing this for the right reasons. You may be better off buying a bigger SSD, or changing your 6-monthly-reinstall plans (to include all software).