GGS (or GCS) glass screen protector - fits very neatly and does a good job.
Not too expensive either if you get them off the 'bay. Plastic film type are pants in comparison.
...or how about this one on Amazon? Seems to be the same but minus the eyepiece.
Don't you have to stick that on, though?
I have had a cracking set on mine for 6 months, they haven't scratched, can't be seen and haven't peeled at all.
Doesn't the 7D come with a screen protector already fitted?
Got a Giottos glass one for my 5DMkII - it's excellent. Cost about £15 from Amazon