Really, no arguments or flames please. This is more of a pick your favorite than discuss the differences. I've never played Arena. I've dibbled and dabbled in Daggerfall a little and put a few hours in a few different characters in Morrowind. Oblivion I sank my life into and Skyrim.. eh, I sank maybe 30 or 40 hours over the last couple of years.
Arena? Can't comment. Neva eva eva eva played the game, though I've watched a few playthrus here and there.
Daggerfall? Very open ended (from what I remember.. I wasn't very old (I'm 19!)) and so many skills and what-not. Took me like 6 hours to get out of the first dungeon and man-eating controls to get used too. Still can't really comment on it too much. Oh. And I hated those nude spider women. Ugh they used to give me nightmares. A few cool points I do remember of this game was that you could ask pretty much any question to anyone and get the answer anddd YOU COULD LEGIT BRAKE INTO PEOPLES HOUSES! I loved sneaking thru someones window and breaking in but sadly I don't really remember all the things you could steal. Daggerfall really was what set the standard imo what brought Elderscrolls what it is today.
Ugh. Morrowind. My baby, my big beautiful, dice rolling honey who I've always dreamed of. Morrowind is my personal favorite being that it was the 3rd I played (Daggerfall, Oblivion, then Morrowind). Such a wide a grand adventure with no hand holding or place markers telling you where to find so and so. The world is a magnificent art piece just waiting to be uncovered bit by bit. I'm currently running a Dark Elf character who's level 3 and I've already sunk 6 hours into this character. Boy do you level slow lol. As much as I praise this game, I don't think I've truly ever even gotten into it. The farthest in the mainquest I've ever stepped foot was getting that pitiful dwemer cube for the crackhead guy. But the world itself can be the cause of that. I've NEVER step foot in the northern half of the map yet I've seen so many wonderful and awesome things on the lower half. Life Molag Mar the san village or Vivec, that stupidly giant fortress/city I always get lost in for hours. Oh and just yesterday I found a giant mushroom that I could climb up too and received an awesome fortify agility pendant off a dead bird. O.o Cool! I'm actually currently stuck trying to find this city by asking directions every where I go. I love that so much! It's like a real adventure. Thus an older adventure with older gameset rules but an adventure none the less.
Oblivion! Oh what a grand it was. So many girlfriends I lost playing in this world. I loved it and loved it more the next day. I remember having such high level characters and god, who can forget "HI, I'M YER BIGGESTZ FAN." Oblivion was the first ES I had ever played and I actually never had a clue the series existed (except Daggerfall but back then, Daggerfall was Daggerfall and not the ES in my eyes) until then. Would still be my favorite if I never went back in time and played Morrowind. I loved the beautiful, fantasy looking world and the graphics were to die for at the time. Just really hated that scaling system. And the ending of the main quest? Yea.. you were just kinda there. And my spears, WHERE ARE MY SPEARS AND CROSSBOWS? They took away some of my armor pieces too? :/ Why are all of these dungeons SOOOOO easy? Where did all of my skills go? Agh oh well. At least I got Mehrunes (sp?) Razor. And Wabbajack :3 Anddd of course my favorite DLC of any Bethesda title thus far with the madman himself. Shivering-****ing-Isles. Oblivion took my ups and downs but it was also the first ES I really got into so + points all around.
Skyrim. Okay, now ugh.. here's my conflict. I LOVE Skyrim. Picked it up on day one and lost yet even more girlfriends. I've ran multiple characters under multiple different play styles and never really got bored until one day I had realized that.. well quests aren't quests and object aren't hidden if I telepathically knew where 'magical orbstone of fiery blood fang' was 50 miles that-a-way. Of course, Oblivion did this too but this was before I had played Morrowind and I feel like I needed that little hand holding to truely easy me into the ES series. Skyrim was beautiful, a beautiful, beautiful world. I never got tired of climbing ever mountain I seen just to be butt****** to death by a monster big balled dragon. I just kinda felt like most quests were tacked on by multitude instead of quality. And removing tagged skills really, really irked me into thinking they were doping their selves up to much and really needed to stop coming up with ideas that moved away from the ES series. My spears, WHERE ARE MY SPEARS? WHERE DID MY CROSSBOWS GO? But oooooh, a beautiful butterfly that I can put in a jar should make me forget about 'dem damned spears and Xbows. But after a while, they just never did. After the novelty wore off I really started to become bored of Skyrim and after realizing that my actions were doing nothing to the world around me, I kinda just felt like it was becoming more of an Action RPG instead of the normally used Skillset RPG. I really didn't care about marrying anyone either, I would have rather had my leggings, pauldrons and all the other nifty armor pieces back. They scaled down to much for me and openly added stuff that I really wasn't interested in. Still a wonderful game though that I would recommend to anyone who like simple open world RPGs.
All in all I'd obviously choose Morrowind as my favorite. Oblivion would fall in second with Skyrim just slightly behind it. Sadly I wish I could rank Daggerfall and Arena but not enough experience to place it.
tl/dr MORROWIND. <333