My best advice for a new player is to play the game all the way through in it's original form at least once so you can appreciate "what it was" with both its beauty marks and its warts. That's advice I give for most any classic game, but especially with Diablo. You can complete the entire game in just a few days or even a single day if you've got a good chunk of time. And it has a very high replay value, so you will almost certainly want to play again. After you've played the plain-vanilla version a time or two, look for mods which mitigate some of the things you didn't like and enhance the things you did like.
As a general recommendation for "After You've Played It a Time or Two" mods, I would suggest "The Hell 2" and "Belzebub". Both of these mods add a significant number of actual new features to the game -- such as higher resolution support, expanded storage options and even a crafting mechanic and restored/cut alpha-version content with Belzebub. They each attempt to modernize the original Diablo experience, but in different ways. And that's why I *strongly* suggest experiencing Diablo in its original form first: so you can fully understand and appreciate what each of these mods brings to the table.
By experiencing and understanding what the original game is, you can better appreciate what each mod provides. Don't just slap some mods on and assume "this must be better because everyone says so." Experience the game in its original form first and you will, at the least, realize WHY each mod is better. And in some (many?) cases, you may actually find that you prefer the original experience over someone else's personal preference.
Post edited November 14, 2019 by Ryan333