Why are all of the great titles coming out now sequels?

Supreme Commander 2
Fable III
Starcraft II
Command & Conquer 4
Fable III
Civilization V
W40k II: Chaos Rising

Kinda depressing and exciting at the same time.

Because original ideas are too risky these days. It's just easier to just tack on another number to a well established franchise then try to venture into new territories. :/

Fable III has me excited though.

This is the problem with the gaming industry. They re-use titles that have been clearly established as popular, and tries to water the 'series name' down so much that it's nothing like the very first game, or etc. I'm not saying all games will have failures like that, some games just keeps on going because people enjoys it for the brand-name more so than content. I think Final Fantasy is one of the fewer exceptions because the game-play content as well as difficulty increases (though this can be debated, because every game that's out these day has an Official Guidebook). Power Rangers for instance, is on-going. Not a lot of people in America watches it as much as back then. But they still try.

Fable 3 twice? I guess you are pretty happy about that. Civ 5 I want.

Fable III? Great? You have high hopes for this one, huh Fiel? Hopefully Natal can help the series pick itself back up.

What'll be more depressing is all of these games failing to reach their potential. That's the real problem with most sequels.

You forgot to list Fable III, bro. Anyway, I think it has more to do with marketing and commercial purposes. Like what Disney does: did Mulan really need a sequel? Did Cinderella who lived "happily ever after" after the first movie really need two more movies? I think it's that companies know they can play on people's nostalgic feelings and release/remake/continue something people already liked. The Smash Bros series since the n64 was pretty great but now Nintendo can and has milked a lot of profit by "remaking" (term loosely used) a game in same the flavor for each of their new console because they know it will be popular. Whatever console Nintendo dishes out after the wii is bound to have a new Smash Bros game to come with it. Coming out with a completely new game is refreshing but there's also a chance it might not be a hit.

Most sequels suck, but I can see the point in making a sequel when the game released before was over 10 years ago.

Starcraft II forever =D.