The first MMO I played was Ultima Online. And I think it was the best game I have played to date. The graphics weren't great but the freedom was amazing. You could do anything the game offered without have to start a new charcter. You could change your skills at any time, you could decide your swordsman wasn't fun anymore and turn him into a mage. The possibilites were endless. Unlike most games like WoW where you have to choose to be a certain class and your charcter will never be anything but what they have decided that class to be. To change your fight style you have to start a new char.
The best part of of UO was NO QUESTS and you didn't level. You gained skill as you went, so unless you were at the top of the skill, you got more powerful as you went. Instead of grind to that next level.
I am currently playing WoW and must say, if your not in a raiding guild, its rather boring when you hit 70. The PVP battlegrounds are rehashed kids games (capture the flag, king of the hill, etc.) Only reason I play WoW is becuase of friends and family play it.
If Ultima online would open a server that took the game back to how it was in '99, I'd drop WoW in a heartbeat. The state of UO is sad, the "improvements" over the years have destroyed how the game was unique. UO wasn't about gear, it had 5 levels of weapons and 5 of armor, with only a few modifiers. Crafted items were on par with the second level of the magic items and was in high demand. Now, they have random item properties that are somewhat confusing, crafted items are junk, and the skill systems is totally broken not to mention the PVP system.
As for Sci-fi MMO's, I think the devs haven't hit the right balance and storyline. Warcraft has alot of lore behind it. Thats one thing that Blizzard does exceptional, the storyline has always been great (exception of the latest WoW stuff)
I tried LotR online, nice graphics, but just another guided quest chain. UO was freedom, you did what you wanted, when you wanted. The PVP was anytime- anywhere, outside of town. Many people complained about this, but it added intensity to the game, you never could tell what the intentions of the char coming toward you were.
Not to mention how cool it was owning a house.