(I use CyanogenMod 9.)
Here's something that bugs me.
Say that someone sent me a few text messages or left a few missed calls on my phone. I see them as notifications, which is great because it draws my attention to them as something I need to take care of.
But, once I tap the notification to see the text messages or the people who called, the notification is cleared. Sometimes I just want to look at them but still leave them for myself to deal with later.
The way this is done in emails is to mark emails as unread; you can read an email, then mark it as unread so you'll know you still need to handle it. I'd love to have something similar for Android notifications, or any other good solution to this problem.