daggerfall v. morrowind
I don't really see any reason not to get both since Daggerfall is freeware (
http://www.elderscrolls.com/daggerfall) nowadays. My favourite TES game is Morrowind but Daggerfall has it's charm too. The games are pretty different, Daggerfall is much more like the rogue-like RPGs with most of the open world content randomly generated while Morrowind is much more detailed, structured and rigid, like traditional PC RPGs.
If you're only familiar with newer TES titles both of these games will look like ass to you so a game focused heavily on exploration like Daggerfall is unlikely to impress you, the game world is huge (like, really big, I've completed the game multiple times yet still haven't seen but third of it, if that) but it feels a lot like a product of it's time when played today, it just doesn't feel all that impressive anymore. The main selling point of Morrowind on the other hand is it's carefully crafted world and really great setting but that of course boils down to personal preference.
None of the TES games offers all that much in terms of moral, psychological role-playing so if that's your thing you wont feel at home with either of the titles.
Also:What is neverwinter nights like?
In what sense? To me NWN was never much more than a campaign editor for internet DnD games with a single player story haphazardly slapped in. It doesn't help that the game was based on the shittiest Dungeons and Dragons setting out there, Forgotten Realms. Of all the NWN games out there the only one I can recommend is Mask of the Betrayer expansion set for the second game, it has the finest story ever written for a video game. It's so good it makes the poorly paced Neverwinter Nights 2 worth playing.
Is baldurs gate 2 better than 1? why? Is it true that it inspired story telling arch type for games like dragon age origins?
Baldurs Gate 2 is better than Baldurs Gate because Baldurs Gate is fucking brutal to play now if you're not accustomed to bullshit Second Edition Advanced Dungeons and Dragons game mechanics.
I don't really know what you mean by "story telling arch type". Story arcs? Archetypes? I'd say NWN had much bigger influence on Dragon Age in terms of how the story moves forward and game world design. And when it comes to the story arcs of those games I'm sure they owe a lot more to fantasy literature and pen and paper games than PC RPGs, since neither Baldurs Gate or Dragon Age has that great of a story, compelling and gripping sure, but nothing more than some easy escapist entertainment.