The Icewind Dale dilogy is a more combat-oriented, less story-heavy approach to D&D games than the Baldur's Gate series. IWD1 in particular revolves primarily around combat; most of the interest comes from the changing settings. IWD2 has more depth, and as the last D&D game made using the “Infinity Engine” it is widely regarded as the most sophisticated of them all in balance and controls, if not in story (it is also the only Infinity Engine game to use D&D 3rd edition rules).
“Infinity Engine” games, which include the classics “Baldur's Gate” and “Planescape: Torment”, use a top-down, isometric 2D perspective for controlling your party. The absence of 3D may be off-putting to gamers used to Oblivion and Neverwinter Nights; but controlling a party of six heroes is hopelessly clumsy in 3D, unless you grossly oversimplify the control system. After replaying Neverwinter Nights 2 and Baldur's Gate recently, I am more convinced than ever that 2D is just better for managing complex battles. Like other Infinity Engine games, IWD makes up for the lack of 3D by giving you beautiful, hand-crafted environments.
The big difference from other Infinity Engine games is that you create and manage the whole party yourself. There are no NPCs to join your party, have conversations with one another, even fight amongst themselves. This makes for a somewhat more lonely-feeling game. For IWD2 at least you can check out the “IWD2 NPC Project” from http://www.gibberlings3.net/…ds/index.php, a mod that tackles precisely this lack. While you're there, also look over the IWD “Tweak Packs” and see if they're to your taste. Use common sense, though – they can make the game too easy if you go overboard.
If you've played Neverwinter Nights 2 and have been left hungering for something a bit meatier, the IWD dilogy is an excellent choice.