I keep a "revolving list" of strategy games that I play. I usually play one until the 'magic' wears off, and then move onto something else. The good games are the ones that can draw my interest again a few months later. Most games don't 'make the cut'.
TBS: Civ IV, GalCiv II, and Age of Wonders: Shadow Magic.
RTS: Dawn of War: Dark Crusade, Rise of Nations, Battle Realms, Age of Mythology, and Age of Kings: The Conquerers
I find that most unsuccessful TBS games are missing a vital component (or two) that make such games fun in the first place. For a game like Disciples II, it's diplomacy and/or a robust combat system. For Warlords or Dominions, it might be graphics, or few non-combat options.
It's rare to find a good TBS game that get's most (if not all) of the basic elements (expansion, diplomacy, combat paths, non-combat paths, finance, technology advancement, etc.) For instance, I love Age of Wonders and GalCiv2, but both games have 'luke warm' diplomacy meta-games. (At least they include something, though.) By contrast, Civ IV may have excelent diplomacy options, but it's combat is unintuitive/frustrating at times. Age of Wonder's tactical combat is still incredibly fun to play.
A lot of the RTS games out there are just terrible, in my opinion. Most are Warcraft 'clones', complete with all of the limitations that made the Warcraft games utter crap to begin with: Incredibly dumb AI (so the game has to use 'cheat' bonuses in place of scripted routines), lackluster 'tech trees', uninspired/cartoonish graphics and combat (that feels like a cartoon), etc. I still detest Warcraft III to this day. Warcraft II was fun for a brief period, until more innovative games came along. I still don't understand the Starcraft phenomenon; it's easily the most overrated RTS game out there today.
Which is not to say that some of the RTS's I listed don't have problems. The Age of Empires series has had its share of problems (balance issues, 'age of buildings', and rushing/flushing strats that ended games in seconds). And RoN was in serious need of a graphics upgrade from Day One. But, on the whole, I find only certain RTS's to be of any real value, especially if they are ambitious and try to push the genre forward. (AoE III, for example, is just AoE II with a new graphics; the gameplay is the same; hence, not worth it, especially since AoE's combat hasn't changed since AoE II.) RoN is ambitious, even though it's graphics suck horribly. And games like Battle Realms are just so unique, they tend to hold up well. DoW is one of the best RTS's out there: it just has the style, polish, and overall fun to be an instant classic. (I never had that reaction to Warcraft, even though I could see Blizzard's workmanship. It's like Rise of Legends: it looks good, just not much 'game' there.)
Then there are fun RTS/TBS 'hybrid' games, like Chaos League, Freedom Force, etc. which almost defy genre categorization.
I go for originality and gameplay. If it's been done before, and I know about it, it's not going to impress me much.
