Which is the best Command and Conquer Tiberium (RTS) game?

I don't really like that series much (started way too late), but so far I'd take Tiberian Sun over the other games in the series.

BTW, voting one option in the poll can also be applied to expansion packs - like voting Tiberian Sun Firestorm through Tiberian Sun.

If we're talking about how good they were relative to all games at the time of their release, the original C&C is easily the best by ten billion miles, but if we're not adjusting for inflation, C&C3 is easily the best.

Not that C&C3 is a particularly good game, but the C&C series does date back well over ten years and each game was an incremental improvement. In other words, TS made TD obsolete, and C&C3 made TS obsolete.