Of vanilla items,
I (as opposed to my characters, who like all sorts of things) like:
Fur, except for the female cuirass. I particularly like the helmet.
Leather, except for the helmet.
Mithril
Iron
Ebony (certainly my favorite)
Of mod items:
Almost everything by http://www.tesnexus.com/modules/members/index.php?id=432558.
http://planetelderscrolls.gamespy.com/View.php?view=oblivionmods.detail&id=5255
http://planetelderscrolls.gamespy.com/View.php?view=oblivionmods.detail&id=2182
http://www.tesnexus.com/downloads/file.php?id=33608
http://www.tesnexus.com/downloads/file.php?id=32794&navtag=file/images.php?id=32794&tab=3 (though the female cuirass needs a slight fix to stop the cloth on the front from clipping the armor and I sure wish I had either the software or knowledge to do it and would sure be indebted to anyone who did and did
).
Tona's Whitesquall (it seems to have been taken down from TESNexus? I did find a link to a http://ludicrousmods.com/tona-whitesquall-gallery/ of it though).
I was mostly impressed with http://www.tesnexus.com/downloads/file.php?id=33179, though the cuirass part (it's a one-piece) is a bit too simply rendered. All in all, very nice though.
And I love http://www.tesnexus.com/downloads/file.php?id=24756. It's absolutely perfect for a wholly evil Argonian.