I was not sure if this issue should have been placed in a specific games' forum, so I hope that general discussion is an appropriate place to ask for help. This is also my first post in the forums, so I apologize if this topic is nonsense.

There is a slight problem I have by way of completing games, namely, that I don't. Perfect examples of this are Baldur's Gate and Baldur's Gate II. I purchased these games while they were on sale back in September of last year, and have tried to start the saga numerous times, but I just can't. And this issue is not specific to PC games, it also applies to my Vita, PS3 and 3DS libraries. When left to pick a game on my own, there are too many to choose from, and I will switch from one game to another after roughly 4 hours, not touch the game I was previous playing for 1 to 2 weeks, and then restart my campaign for no particular reason.

This summer sale has (and I'm not sure if this is a boon, or curse), vastly expanded my GOG library. And now that the summer is here, I have decided that I would like to dedicate my free time towards every good old game that is both in my library, and highly recommended. At this point, the list is:

Aarklash: Legacy
Arcanum: Of Steamworks and Magick Obscura
Baldur's Gate I: The Original Saga
Baldur's Gate II: Complete
Fallout 1
Fallout 2
I Have No Mouth, And I Must Scream
Icewind Dale I: Complete
Icewind Dale II: Complete
Magrunner: Dark Pulse
Neverwinter Nights 1: Diamond Edition
Neverwinter Nights 2: Complete Edition
Planescape: Torment
Primordia
The Swapper
System Shock 2

I just don't know where to start, and my experience with >10 year old PC games is limited to Fallout 1 and Fallout 2, both of which I still have yet to complete! Planescape: Torment is one specific game that I would like to start with, but I have heard from others that it's story is particularly marvelous, making me the slightest bit worried that other games with still high-quality stories may pale in comparison.

This community as a whole has a massive amount of experience with these good old games, which is why I am asking you all to help me decide what games (2 or 3) to start with, and in which order the RPGs' should be played. And again, I am sorry if this topic is just drivel.

UPDATE:
Primary: Baldur's Gate I
Secondary: Fallout 1
Tertiary: Whichever quality game best contrasts with the primary and secondary choices (Magrunner: Dark Pulse, The Swapper or Primordia).

Pretty much all or most of those games are highly rated and very well liked, I'm not sure if you could see a pattern emerge where a couple titles get recommended more than the others, and I don't think you could really go wrong picking any of them per se. I haven't finished any of them myself either although I own all but 3 of them I believe. If I were to pick one for myself to start with at the moment I would pick Baldur's Gate 1 as it is the oldest of the bunch I believe and I prefer to play older to newer in general.

I think I've completed 4 games in my life not counting the 1st Contra which I was able to do because of the 30 man code. I have severe ADD when it comes to gaming so the OP has nothing to feel odd about. :D

The matter Torments you. That is an omen.

Fallout 1 is actually not that long. If you have trouble finishing games, that might be a good one to start with.

I had the same problem and eventually got fed up with the fact that I would start games but never finish them. I wound up writing up a list of all the games I own - they are divided by platform, (DS\3DS games is one category, PC is another,) and I've started writing checkmarks next to each game as I finish them. This might be too much work for some, and maybe the fact that I'm keeping track might seem like gaming becomes a chore, but for me this method works very well as I find putting checkmarks by my games to be a motivator for me. :)

It used to bother me that I have hundreds and hundreds of unfinished games, thousands if you count free iOS games. But now, I try to remember that games are for fun, and if I never 'finish' a game it doesn't really matter.

The collecting/bargain hunting/ hoarding of games is probably as fun for me as most of the games, but that's another topic.....

I hate when I'm stuck in games with no clue what so ever on what to do.

I enjoy playing games in Chronological order, and my biggest concern was to play the strongest RPG, in terms of writing, and then work my way downwards in regards to quality. But you, and others, have made a very strong case for starting with the Baldur's Gate Saga. So thank you, I'm going to have a great time starting Baldur's Gate I after tonight's exam review! Thank you. I've not actually looked into the life-length of most games that I listed, but I have been hoping to play through the Fallout series in chronological order this summer. I am definitely going to have Fallout 1 as my off game! I really like this idea, actually, I love it. And I'm going to use it, so thank you very much! I think this will absolutely help me in whittling down the list of not-yet-completed games.

Play Fallout 1 first, easy to finish in some weeks and to introduce Fallout 2 (and Arcanum to a certain extent).
Play IHNMAIMS only the night, just to be in the atmosphere.
Keep Baldur's Gates and Torment for long winter nights, or you will never see the sunlights during the Summer !

Why don't you own Sacrifice ?

I admit, I have similar issues. Too many games, barely any of them even started up, so when I try and go and play a game I end up going back to an old favourite rather than trying a new one. I also have the issue where I tend to want to play a game series in order if at all possible -- I want to retry Fallout 3, but I know I've got 1, 2, and Tactics in my backlog.

I, uhm, I don't know. I've never heard of Sacrifice. Should I add it to my wishlist?

It's comforting to know that others have this sort of problem. And I completely understand, for the longest time I would just play Fallout 3 and Chrono Trigger when presented with the "which game should I try and play?" dilemma.
Are you hoping to start any games in particular, in the near future is?

I actually came to GOG for Baldur's Gate, but played Torment first. Wasn't disappointed, can only recommend it!