I believe you could use regular notepad but it has to have admin. rights. With Notepad++ you just right click on the file and then edit and save. No worries about admin. rights. But I don't think your worried about editing the host file now anyway.
If you wanted to remove doubleclick from the host file, all you do is find it in the host file and add a hash in front of it like this:
# 0.0.0.0 ad.doubleclick.net
The host file is found here:
C:\Windows\System32\drivers\etc\
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