UPDATE 07/01/13:

Roughly two years later, I've finally started BG1 and am enjoying it immensely. I decided to resurrect this thread so others in a similar predicament could benefit from the helpful recommendations in here as well :)

ORIGINAL POST:

I haven't played any of the classic Infinity Engine/Aurora Engine CRPGs. No BG, Icewind Dale, Neverwinter Nights. Heck, I haven't even played Planescape.

I'm committed to experiencing these - which one should I grab first? I'm a fairly decent modern RPG player. Really enjoyed the tactical gameplay of Dragon Age Origins on the PC for reference, but one of my first loves was the Diablo series. :)

If you enjoy the combat aspect of RPG's more, I would be tempted to suggest the Icewind Dale series, as they are low on story, high on combat. You get to roll all the characters and create your own party. On the other hand, if you are unfamiliar with the mechanics of D&D, I would tentativly suggest Neverwinter Nights, as it is a lot more forgiving game, and requires less understanding of the mechanics to play it well IMO, and you only have to worry about one character.

If you like a deep and interesting story i recommend starting with Planescape Torment and then Baldur's Gate 1

I recomend both BG I & II as I am enjoying them right now. you have to be patient as the combat has a little bit of a learning curve but with patience and you'll get the game in no time.

That depends.

Neverwinter Nights is heavily action-oriented, and pretty much a solo game. Sure, you can have one companion following you, but not very much control over them. (I'm talking about the main game, I haven't played the expansions yet.)

Icewind Dale 1 and 2 are similarly action-oriented, but you get to create a party of six adventurers (there are no NPCs to join you unless you install certain mods). The games are not actually connected beyond being situated in generally the same place (the icy north of Faerun) and sharing the same name.

Baldur's Gate 1 and 2 have a decent story, centered around the protagonist, with the second game directly following the first (you can import the final save from the first and continue playing the story with your own character). There's still quite a bit of action. In single player you only create the protagonist and can then have up to five NPCs join you, if you start a multiplayer game (even playing alone) you can create up to a full party of 6 yourself. There are a crapload of joinable NPCs in both games, and all have their own personality, so you can mix and match pretty heavily.

Planescape: Torment, last but not least, is heavily story-based. I think there's just a handful fights throughout the game you can't avoid in any way, with the rest being possible to either talk through or avoid in other ways. You don't get to create any characters, though you select the main stats of the protagonist, and get a few NPCs to join you during the game's course.

Planescape Torment if you feel like reading a book while playing your game. There is a lot of reading, and it is one of the (if not THE) best RPG I have ever played. And all that just because of it's story and player's power of choice.

BG, on the other hand, is fairly typical fantasy story - not a bad one as well. And it focuses on combat a lot more. If you're not the hardcore old-shchool gamer, I would probably just recommned getting BG2. BG1's story is all summed up in the beginning and it's closer to modern RPGs, like Dragon Age.

I'd recommend Planescape: Torment, because it's got a fantastic story and the combat is hard but not so frequent that it will overwhelm you. I'd suggest doing a little reading up on the game first, but a lot of it is story driven.

I'd start with BG1 while playing Neverwinter Nights. That's what I did and it worked out well for me. :D

I'd recommend starting with the Baldur's Gate saga and continuing with Planescape: Torment. Simply because they run the same engine and all the AD&D stuff and its controls are easier to learn in BG. Combat in PS:T is pretty much just a nuisance that gets in the way of the game and if you are familiar with the interface, you can plough through it faster.

If you like turn-based combat and leading a party as opposed to a single character, Temple of Elemental Evil might be for you. The story is okay, but it really is a combat-fest (a fun one).

If you're lookin for a Diablo type of game, your best best is Neverwinter Nights; its official campaign, or expansions, or fan made games using their engine or PW servers.

If you're looking for a Dragon Age: Origins type experience, then BG1 or BG2 is the way to go (though perhaps IWD1 or IWD2 may be closer, in terms of combat; it comes w/the catch of lesser emphasis on roleplaying though).

Planescape: Torment

Play the BG games first, since they're like a superior DA:O.

Then play Planescape.

If you still enjoy Infinity Engine combat at this point, play Icewind Dale.

NWN singleplayer is like Diablo sans atmosphere, which is roughly equivalent to eating wallpaper paste.

I love Planscape: Torment juss as much as everyone else here, but the OP gave examples of the type of cRPG's he wants to play, and Planescape doesn't exactly fit either the Dragon Age or Diablo molds he gave as example (partly b/c there is no other game comparable to Planescape, and partly b/c its not very combat heavy).

If you like Diablo-style gameplay but are also looking for a story to go along with it, why not give Divine Divinity a try?