You want nothing ... NOTHING to do with those first few appearances of Thanos. Stay away. If you think too hard on them, he is ruined as a character. He was nothing like he is today. Well, his first couple of appearances at least. Ever see his helicopter?

Yes, just to avoid confusion when he parked at the mall, the great Thanos had his name printed on his helicopter.

Can't think about this too much hahaha
You want some good stories, just start with THANOS QUEST, a two-part ... mini-trade (I forgot what Marvel called those. They were like a double sized issue of a comic, but had a glued spine like a trade) and then go from there. That is after Starlin really found "who" Thanos was, even though there are some cool Warlock related stories as well, the Thanos we know really started in Quest and ran through the first couple Infinity Gems mini's (Gauntlet and War. Not included Crusade which was god-awful).
Kinda surprised that Wiki didn't mention MARVEL: THE END. A story that happens between ABYSS and his own THANOS title. That's odd. Kinda relative if you read THANOS I think. At least the first part (though they do a decent job of recapping it on the first issue)