As I said, the problem is not with the download. If that was the problem, then you would not see the icon in your other account.
And, your choice of browser is also not an issue (again, the other user account would show the same problem, too!)
Boot to your Recovery partition (restart while holding command-R) and run Disk Utility. Do a Repair Disk (different from Repair Disk Permissions, which wouldn't help you, anyway). If that Repair Disk passes without any problems, restart. and check your icons.
If that doesn't change anything, you could dip into your user folder/Library again, and try more file cleanup.
So, in your Library: remove this stuff: (I'm done with messing around, if you are
)
The Caches folder (just drag the whole thing to the trash)
In the Preferences folder, delete the ByHosts folder
The list of files that I previously posted here would still be good to delete again.
Some of those .plist have associated lockfiles, with much the same file name. Delete those lockfiles, too, if you find any (not all will have associated lock files.)
And - restart again.