I just came back from a very long absence from TWHL, and I am pretty happy! Almost done with DOOM 3 and ending Nova Prospekt in HL2; can't wait to get to Source mapping.
My rule is to beat the game first and then when I start mapping I don't spoil stuff to myself. I JUST CAN'T WAIT! I'm already thinking of doing a simple map with Rebels vs. Combine, LoTR style! Oh yeah baby!