Originally Posted by ayush29k
Check the nightly changelog, there might be problems with the USB storage in this build.
For youtube, try reinstalling the app.
You can also flash a CM7 based custom rom, it will give better performance, features and looks as compared to the default CM nightly.
I have tried reinstalling YouTube a couple of times (adding to OP), doesn't work. USB was fine before, I tried MIUI and after it was FCing I switched back to CM7, I also use EX Launcher so I don't care about the default looks.
Also, any good "CM7 based custom ROM" examples?