Diablo and Hellfire were good the first time through, but fairly boring after that.
D2 and LoD are much better IMHO.
But, they are improved upon greatly by a mod for D2 called Eastern Sun.
Want to rearrange your skill points when you are lvl 75 - no problem.
New and improved skills.
Horadric Cube recipies to improve your items, make new crafted items.
Many new things to use in recepies and crafting.
New monsters.
All new uniques and sets.
Make a socket in an item, pop in a perfect gem - take the gem out if you want to try another.
Here is the link to the main website for ES.
http://homepage3.nifty.com/miyoshino/es/es3top.htm