Well, tho I started late, it was actually a good time to appreciate the game it is, the game is wonderful, Prime Echoes seems to be Prime 1 but better in several aspects, the power ups seem to be better delivered, its more intuitive when it comes to know where to go next etc.I second this, but I also recommend you play the rest of the Dead Space games. Well, maybe not Ignition.
Also, super glad you enjoyed Metroid Prime as much as you did but I think in a lot of ways I prefer playing them with a GameCube controller, so if you get the chance don't hesitate to try it. It's very intuitive actually.
I will play the Gamecube versions for sure, I watched comparisons long ago and if I remember correctly some physics were better in GC, I should get a GC controller first, using an Xbox 360 controller can't be the same.