So I just started playing the original Mass Effect a week or so ago, and I'm not even 10 hours in. What DLC over the course of the 3 games is essential to get the best version of the ME story? Can one get the majority of the story through the base game alone? I heard the original ending is carp (no need for anyone to expand on that... I get it), so is there a better ending in one of the DLCs? I'm looking to spend as little as possible, but I'm not opposed to a purchase or 3 if it makes the game more complete.
To expand upon what has already been stated (because I can't NOT talk about ME)... You technically can get by with the base games for the most part and you'll get the story. However, there are many DLC's that add characters, story, background and combat abilities that I personally think should not be passed up. Aside from appearance, weapon and armor DLC (some of which I do like) here is my game breakdown:
Mass Effect:
Bring Down the Sky - Adds a small piece of story that will carry into ME3, gives you some additional leveled loot at the end and I found it enjoyable to play through.
Pinnacle Station - Nothing more than a survival/horde mode type DLC. No story connections. Pass.
Mass Effect 2:
Cerberus Network - It's free, so get it. It includes Zaeed and his missions/dialogue, some weapons, armor, a vehicle and it's associated missions (which I find annoying, but whatever).
Lair of the Shadow Broker - Quite possible one of the best DLC's of all DLC's. It has loads of story carryover, extra weapons, resources, upgrades and it's just plain awesome. Get it.
Kasumi: Stolen Memory - Again another character and her missions/dilogue. Carries into ME3. You get a nice weapon and I enjoyed it, so I'd recommend it.
Overlord - Carries into ME3 slightly. Again, more resources and upgrades. Pretty enjoyable, recommended.
Arrival - Definitely clears up the beginning of ME3's story in my mind. Gameplay isn't bad, but not up to the others here. I still had fun with it and can recommend it to the ME fan.
Mass Effect 3:
Extended Cut - It's free...get it. I personally didn't have an issue with the original ending, but this adds a lot more without really changing the original intent.
From Ashes - Just like ME2's character DLC. Adds weapon, combat abilities and dialogue. I'd get it.
Leviathan - Adds to background of the over-arcing story. Adds weapons and combat abilities. Gameplay is so-so, but I think the story connections make it a worthwhile purchase.
Omega - Adds weapons and combat abilities, but little in the way of story. I'd say ME fans only need apply.
Citadel - Probably the best farewell love letter a DLC could be. The main story is fairly short, but the entire DLC is rather long if you want it to be. You can get some nice armor and fight alongside your friends from the past. If you got everything else, no reason to not get this.