My name is Volourn. And, thankfully, there's no connection to that annoying geit. Besides, the charcter Volo is a long time FR character. BIO didn't create him.
Whgy get NWN1 over NWN2? I never said that. I said get that as well. It offers three different full campaigns, and a handful of shorter ones. It likely gives a background to the NWN2 OC setting. You get access to a bunch of rather good player made modules and PWs as well, and tons of material that will takes months if not years to be seen in NWN2 like epic levels (if that's your thing), hundreds of new monsters, more tilesets, pretsige classes, more spells, including epic ones, and tons of other stuff.
And, like I said, it's not horribly expensive now and there's lots of stuff to be had.
You don't need to get it; but it can't really hurt.