It is possible to get your installed state back on an installation medium using Windows AIK,
for mass installations this is fine. But for a single installation it isn't worth the time...
Not to forget it's better to look for the latest drivers and you will still have to update anyway.
Lots of years have passed between Windows XP and Windows 7...
The size of the OS has changed, but the HDD did too so that really shouldn't be a problem.
It's hard to decrease the default installation size without removing the necessary features.
I would suggest you to take another approach of backing things up. The installation size of Windows is a DVD, if you are trying to back-up your installation you might as well reinstall instead of doing a restore.
Try the backup and restore tags here at Super User and you might find a better solution to this,
if not, then it might be a valid reason to ask a new question on that issue... Maybe a duplicate appears?
Let's see where Windows is spending the most data in my case just to learn from it:
What we learn from this:
WinSxS, DriverStore, Installer and Assembly tend to grow over time.
Features that you might not need are available for easy installation without the DVD.
Windows has a much more stable approach to DLLs.
One can carefully apply compression he might need or delete things he never needs, take caution: While this applies for Speech Recognition and Windows Media Center (eHome), it might not apply for any random fire you will encounter and it is best to not tamper with those.
As the Side By Side article stated:
If you delete components from the WinSxS folder like the manifets or the assemblies, etc, you could be in trouble. Each system would react differently. What may work for one could break another! For instance, if you install a program that requires that particular assembly, which you may have deleted, then that program will just not run! Compressing the folder is also a no-no, as it could cause problems during Windows Updates or while installing a Hotfix.
After using this installation intensively for a year, it seems time to do a reinstall in the near feature.
Please note: The Pagefile takes space too!