Honestly I don't care to use artifacts much. I'll usualy just use a custom enchanted weapon and a set of custom jewely. I don't even wear armor anymore because it's too easy to find now that I know where all the best stuff is. With this lineup of enchanted gear I'd say that Azura's Star is my favorite artifact.
If I must choose a weapon I'd say sunder is my favorite. Considering it's strength fortification it's definitly one of the better weapons in the game. I always liked it's subtle design as well. Hearing about it and seeing pictures of it, I was expecting it to be a huge maul like all the war hammers. I was pleasantly surprised to see it was one-handed.
Spoiler If only I didn't need wraithguard to use it. Heavy armor isn't my forte.
If I must choose a piece of armor I'd say the Cuirass of Savior's Hide. Like I said, good armor's too easy to find (this especialy so) but by the off chance that I do wear armor I usually use light armor. Besides this is about as normal looking as high end armor gets in Morrowind.