I wouldn't bother with the first two. Great games for their time, but time has passed them by. Morrowind is a very solid game, but if ugly graphics bother you, I would stay away. Oblivion is a masterpiece. One of the best PC games of all time. Still play it now and again.
There is an official HD patch for Morrowind that makes it look like Oblivion so graphics is not a reason to not play it. Plus it has at least four times the content of Oblivion and it's at least twice as big as Skyrim.
By the way, I really hope they're making an addon for Skyrim that features Morrowind because you can actually go to Morrowind in TES5. You have to cheat because there's an invisible wall but all of the landscape is actually there, Red Mountain, ashen deserts, everything. Obviosly there's nothing much to do there but you have to wonder why they would even bother to include it. My fingers are crossed.