I think everyone can appreciate a high level of detail. Like for me, I don't just put the streets in there. I try to include major landmarks, throw in bodies of water (rivers, ponds, lakes, what have you). Think about how the town came into existence. Its history can also play a role in how it grows. What is the geography? Is it on an island? It will have to grow up instead of out. There will be more bridges. Small considerations like this help the map come to life. It's not just about the street layout, though you can still do some cool stuff as far as that's concerned. Buildings are another awesome aspect, in my opinion. It's easier for small towns, but I sometimes try to get buildings in even huge city maps. Do a zoom to the similar level as your map on Google maps and see what buildings are there. That'll help you with scale. But I like to see maps like that and wonder what each building is. It helps transport the reader/player/whatever there.