I've currently got my best run so far on Nethack after two years! I'm level 8 with an AC of -2. For me, that's total domination considering I still don't have a clue on what I'm doing. But yeah, I probably wouldn't want to hack it either just because of all the spoilers one would find. For a great diversion, you should look into ADOM over at ancardia.ath.cx I actually enjoy that about 10x more than Nethack.