In PvT, 2 Gate goon is a good safe build to work with, much easier to hold off 2 Fact rushes and your economy will still be decent. Just remember to keep expanding and making workers, while you build up your Dragoon/Zealot/Arbiter army. Don't forget upgrades.
PvZ, 4 Gate 2 Archon is a very good solid build to work with, but scouting is basically the most important thing in early-game PvZ. If Zerg gets an early gas, make 2 cannons before expo. No third hatch, then you better put up some cannons to defend the cheese. 12 Hatch or Pool, you can make Nexus before Forge, and early Hydras usually indicates the damned 3 Hatch Hydra rush. 3 Hatch before Pool, you could try a cannon rush lol.
PvP, depends on the map. On rampless maps like Fortress, 2 gate Zealot will be prevalent and you must match Zealot numbers w/ the other player unless you have awesome micro. Long rush distance maps, Forge FE, DT Forge Expo and 1 Gate Core Expo will be more common. Otherwise on a standard map like Fighting Spirit, 1 Gate Range Obs/Reaver will be pretty much the standard build.