And if you do not liked Planescape and you will hate it even more 
As it was in my case. Like BG and BG 2 but never liked liked planescape, never grabbed me.
True! That's a good point: PS:T haters will probably hate MotB too (though...at least the graphics in MotB are prettier? Heh.)
The best nwn game for me remains Hordes of the Underdark expansion. So epic.
I must respectfully disagree. HotU is the best in the NWN 1 franchise (at least, for official expansions - I have to say, my absolute favourite NWN 1 mod is still the Almraiven series by Fester Pots), but MotB blows it out of the water as far as I'm concerned - though this is probably because I really like having a well-told story in my RPG.
The thing about HotU is that the first act is really, really hard for me to get through, because it's basically a dungeon crawler that's one act long; honestly, I would just play IWD I/II or heck, even Torchlight/Diablo if I wanted dungeon crawling and crazy stacks of loot. They do it better. And the second act...well, I liked the attack on Lith Myathar (sp?). But that entire act is basically going from Point A to Point B to Point C to pick up allies, a very simple way to fill up a game (which Bioware disappointingly rehashes in DA:O), and it really only gets GOOD in act 3, which is the last act. This is...waaaay too long to get going, in my opinion. Though I will acknowledge that they incorporated the Relic of the Reaper in a pretty clever way in that last act. I remember liking that the first time I played.
But yeah, the only NPC I actually liked in NWN 1 was Deekin. I was pretty neutral about Valen and Nathyrra.
But hey, YMMV.