My scenario is simple: I have my Notebook and my PC. I am using my Pc to play music and movies in my home. Sometimes i download something on my laptop sometimes on my pc – i want to be able to play/control everything from one place remotely trough wifi.

When you are trying to copy something on another computer, there is problems with “access denied” So, on beginning you need to give permission to other computers to make changes in directory.
Here is how to do this when everything else just don’t work:
Vista/Windows 7 :
Win XP:
Right click on folder > sharing > allow network users to change my files
If those steps does not work you can try creating new folder, than copying files from folder you wanted to share, and try to allow network users to change files on new one. It is often bug in windows xp
Set it up, for example:
Remember that network folder(the one on right) needs to have file change allowed.
Then, you can simply sync your files as you want.
I am using RealVNC its works great for me:
Download free edition, alternative link(source)
Download for Windows 7
+ Check out torrents for Enterprise Edition
Alternatively, check out this chart with comparison of Remote Control application and choose something that suits you.
Feel free to write your experience with remote controlling and syncing over lan.