My iMac was in need of a speed boost and I gave it one via a new 512Gb Crucial M4 SSD.
Ok, I may be exaggerating just a tiny bit when describing the installation of the SSD into my 2011 27" iMac. It started off in what I thought would be a disaster but ended up being an absolutely wonderful experience. When I removed the glass from the screen exposing the LCD, I neglected to thoroughly clean my iMac first and ensure there was no dust trapped anywhere. Well there a huge amount of dust lodged in the air intake vents under the screen and all of that dust flew directly onto the exposed LCD. I had read many reports on doing this installation and knew that dust on the LCD was a potentially big problem.
I continued with the installation and decided I would simply deal with the LCD during the reassembly. Everything else went like clockwork and it really helps to have the iFixit Installation Video running on a nearly laptop for reference.
When the time came to deal with the LCD, I simply cleaned the LCD until I was sure I could not see any residual dust on the panel. I then replaced the glass and powered up. Upon inspection, I had managed to get all of the dust off of the LCD. My iMac now has both a 512Gb SSD and the original 1TB HDD. I couldn't be happier!
To everyone doing this installation, my advice is obvious! Make sure you completely clean your iMac of dust etc... before attempting this! Wash your hands well and if you do manage to get dust or fingerprints on the LCD, don't panic. Continue on and deal with the LCD at the end. Play the iFixit video on a laptop if you have one available. Work with a partner!!! It's so much easier to do things with an extra set of hands, eyes, brains. Good luck!