Similarly to what Alice said, appreciating effort made by many in terms of research and documentation especially. Of course having excellent rom hacks by experts is cool too.
There is someone I could say I somewhat look up to. Not many here know him, but talking about a german, veteran GameBoy / gen II rom hacker with nickname of Tauwasser. I don't think he's that active anymore, but you can find him in Skeetendo forums.
Pretty much every time I used to figure out something really cool in my opinion (as an example, I remember writing a tutorial that was somewhat a "hacky solution" in using the partially implemented
Name your mother asm routine from G/S/C to actually name a third character (not just the player and his/her rival)), Tauwasser used to be there to not run you down (although it used to feel like that sometimes as well), but giving opinions on how this stuff could be implemented better, and what you were possibly missing from the correct solution when you were in a trouble. A whole different thing is, did I understand his help back then ("there's this really complex structure here, and once you do this and that, you've got the job well done")
Also in case you want to see something cool from him, Tauwasser used to start this Pokemon Midnight rom hack, but I don't think it ever got even close to being finished. Here's a video clip of a playthrough of the publicly available demo from 2004 (?). Don't know where to find it anymore though.