I enjoy the space combat of STO quite a lot, but unfortunately the ground combat sucks.
Out of every graphical MMORPG I've played -- which isn't THAT many, just DDO, WoW, and Guild wars -- DDO was definitely my favorite thanks to the fact that combat involved more interactivity than idly pressing the occasional number key. That as it may be, I haven't gotten to max level in any of them other than Guild Wars. Guild Wars 2 has made some bold promises that I'll have to see to believe, though. I quit WoW around level 16 or so because the game was just boring me (although I'm told that the elements that bored me three years ago are largely changed now) and I simply decided that I didn't want to keep paying for DDO around level 12 and couldn't find much in the way of free content.
Most people will hate me for it, but... you played the good part of DDO. Sure, story-wise, there are great storylines on DDO (Sharn Syndicate, Necropolis 1-4, and the new Phiarlan Carnival packs are GREAT to read and play), but for most content, the only thing good about the paid modules are... exclusive loot. That's all. And after lvl 13, when you start doing gianthold, the game become a big stalling grind.
Some quests on high-level areas are greatly developed, but you need to repeat the same quests so many times to farm for macguffins that you eventually dont care to check how well made those quests are anymore. You just want to reach the chests fast to proceed on the storyline or to craft your new toy.
And that's why, even being a VIP since 06, i never capped a character. I like the fun parts of the game. I play until level 13-15, and then delete and restart. Since the game became free to play, the new packs are great on the low level range (Sharn, Phiarlan, Sentinels), which made me happy.
I hate to praise allods after they brutally murdered their game with the latest patch but they had one thing going for it.
If you killed an enemy with a crit the enemy corpse went flying and slid a bit before standing still. That made really blowing something up or nuking a group with an aoe more satisfying. Also since the whole game was on big floating islands occasionally you could knock an enemy off with a big hit and that would increase the fun.
The WoW (and mmo in general) pve/pvp combat would be vastly improved if every power gave a unique death animation. It would be a lot of work to set up but they could do it gradually one patch at a time.
Shamus touches on the very thing that has kept me from playing WoW with most of my childhood friends, apart from it being a computer game; the combat. Cooldowns, and just standing still while you repeatedly tap the number keys until your opponent falls over is so boring that I stopped playing after 20 minutes when I tried the game on a friend's account. I don't really get why no MMOs have tried a more sandbox-like approach, like games such as Oblivion, in terms of combat and movement, etc.
Not sure if this has been mentioned; but Nexon's current and upcoming MMOs Mabinogi and Vindictus seem to definitely mix the combat up to be fast paced and interesting;
Mabinogi features a varied combat system with action game elements where every weapon and tactic type can turn into a different game play experience that allows a skilled low level player to take down things far beyond its suggested foes and a poorly played high level to get murdered if not careful, and the "rebirth" system cuts down on grinding significantly
Vindictus on the other hand ditches almost all traditional RPG combat and goes for something that would look more at home in say God of War than World of Warcraft, From the closed beta (I happened to get into it) I can tell that the combat is not only varied and interestingly brutal, but I entirely forget there even ARE level ups to be had many a time, I am too busy enjoying smacking things around and slamming them face first into walls to mind the long "grind" between levels.
Both games are worth checking out if your looking for a solution to repetitive MMO combat, Mabinogi is out and has been for awhile and Vindictus should be available to the rest of the public by the end of the year.