My fave shows why you don't mess with THE SPECTRE...
(http://2.bp.blogspot.com/_6DTj9VwvSB0/S5Pc41ntt3I/AAAAAAAAAF0/N_4Foajz1kU/s1600/adventure%2Bcomics%2B436%2Bspectre.jpg)
Some personal faves.
(http://images1.wikia.nocookie.net/__cb20081222062642/marvel_dc/images/3/3e/LEGION_68.jpg)
(http://upload.wikimedia.org/wikipedia/en/a/aa/Detective_Comics_-609.jpg)
(http://farm3.staticflickr.com/2782/4356667239_e540161c12.jpg)
(http://www.coverbrowser.com/image/crisis-on-infinite-earths/8-1.jpg)
(http://i3.photobucket.com/albums/y60/comiczar/covers/ws7.jpg) or pretty much any other Weird Science/Weird Fantasy comic cover which I bought in reprints when I could although eventually they'd be merged with the Horror titles.
Here are a few of my favorites:
(http://www.capnwacky.com/brodie/drawings/spidermanbuttwhupped/amazingspiderman39.jpg)
(http://tomheroes.com/images/COMIC%20avengers%2012.jpg)
(http://images.wikia.com/marveldatabase/images/3/30/Werewolf_by_Night_Vol_1_16.jpg)
(http://www.wwcomics.com/images/large/IM_51_Sav.jpg)
(http://www.comictreadmill.com/CTMBlogarchives/2011Images/JourneyIntoMystery112-thumb.jpg)
Just for the sheer "WTF???" factor....
(http://www.ep.tc/tod-holton/00a.jpg)
(http://www.atomicpopcorn.net/wp-content/uploads/2009/09/skulls-ghost-rider-cover-by-marc-silvestri-ghost_rider_coverc.jpg)
Not necessarily my favorite, but its a nice bit of artwork.
I remember reading this when it came out....
(http://media.comicvine.com/uploads/0/4/5963-796-6523-1-batman_super.jpg)