Welcome to Windows Seven Forums.
Out of curiosity, I checked my Windows folder and it currently sits at 23.5 GB.
Of that the WinSXS folder accounts for 9.5 GB.
In my view you've got nothing to be overly concerned about.
That said, you can:
- Run Disk Cleanup
- Delete the Windows.old folder if you have one and there is nothing you need in it
- Reduce the size of your shadow storage space
- Invest in a bigger hard drive
- Uninstall any software you don't use
Whatever you do, don't try and compress your Windows folder. Also, leave the WinSXS folder as it is or you may encounter instability problems.
Check out this excellent tutorial by Brink: Optimize Windows 7