1. Incursion classic, tactical, rich and nice in-game docu/flavour (texts) [monsters, items, gods]
2. UnReal World unique and lovely setting/world, tiles only, strong points: free-form, crafting, focus on plain survival/living, interesting things can emerge
3. Cataclysm DDA sweet world-gen, free-form, crafting, driving cars/trucks/bikes, going shopping with shopping carts, lots of stuff here (mutations, cybernetic modules), if you want to tone down on it a bit, there's 'classic zombie mode'
4. Slaves to Armok II (not to emphasize the f in df which is done more than enough) free-form, lovely world-gen, emergent behaviour possible
5. GearHead Arena free-form possible, never advanced the story much myself (no permadeath and fast shop restocking with new items make baby jesus cry), gotta love mecha combat
ADOM, DCSS classic, next best choices after Incursion
IVAN fun (gotta be a bit maso here), but truely a "violent road to death" as is its name, tiles only