I have been struggling to find a pantheon that worked with me and my players for a while so i hope you don't mind a long post.
I have the exact opposite opinion as Wedgeski, dnd is all about the age of myth it needs visible gods messing around with the campaign world. I think gods should be awe-inspiring and big part of every day life. That is an important part of dnd to me.
I find the lore of the traditional DnD pantheons interesting, but i don't use them simply because there are too many goods. Each race has its own god of war, death, creation and so. That fills the campaign with so many gods it is hard to make them feel important in the campaign.
I think, it is a good idea to try to lower the number of gods in the campaign. Make one pantheon to rule them all that all the races worship in different forms, or use a few pantheons that whole regions or groups of races worship. This can be a good source of conflict for the campaign and you still keep the number of gods low enough for them to seem important in the eyes of the players.
Now as for how gods look i like to make them awe-inspiring. Worshiping Bahamut the platinum dragon, or the Silver Flame are more majestic (and cooler) gods of justice then
Heironeous, a knight in shining armor. This also makes it easier to have different races worship the same gods. Not to say you cant use a few human gods, especially if the god is an ascended mortal, but just don't make them all human or elf or whatever.
I try to avoid using the real world pantheons because they are too human centric, however i do use as inspiration for my gods. The Norse description of the
Fenris Wolf charging odin is just epic
"Fenrisúlfr will go forth with his mouth opened wide, his upper jaw touching the sky and his lower jaw the earth, and flames will burn from his eyes and nostrils."
Now that is excellent imagery for a god of destruction. He also tried to eat the moon
Good imagery for the deities is important. It helps you decorate their temples and worshipers and make the legends about them that will inspire the players to play clerics, and pallys.
If you use important and active gods, try not to fall in to the trap of the gods babysiting there clerics and churches, and telling them everything they need to do. Give the gods a broad enough portfolio and agenda that priests of the same deity can disagree with each other. I never take my clerics powers away if they make 1 mistake (gods are to busy to babysit you), as long as the cleric is truly faithful to his god he gets powers (remember clerics have super high wisdom so feel free to smack down any players claim they are just misguided when they butcher the gods dogma). If a divine servant starts to deviate too much, it first falls on his order to correct him, then the other servants of the god (angels and the like), and if he commits a truly horrible atrocity then the god its self could get involved, but this should be the stuff of legends. (like
Lord Soth)
I also try to point out to the players that people pray to different gods for different reasons. I hate it when a pantheon turn it to "Pick your monotheism". I think pantheons are much more fun then a single deity set up.
Your avrage npc will pray to the wild god of the sea god before travel, the god of life when his son is being born, and then beg the evil god of plagues not to take his son when he is sick. Even your cleric of holy purifying fire will pray to the sea god so he dose not end up sinking.
....that is enough ranting for now... but i would be happy to give you examples of my pantheon if your are interested.