The single-player campaign? Boring. Truly boring, a bit of a waste, as there IS potential somewhere stuck in there. And in fact, a big part of the problem of the campaign is that it isn't a single-player campaign, really. It's more meant as a campaign that can be played by more players at the same time, and it actually shows at various points. It's most likely amongst the reasons why the focus isn't really on the player at all, he's more of a courier who watches most things enfold around him.
The campaigns for the two add-ons are much better, in my opinion. Shadows of Undrentide is a neat campaign, nothing to jump around on my head for tho'. Hordes of the Underdark, which is a strict Single-player campaign, is the best of them tho'. Bioware really managed to cram most out of the engine, and the scope of the story is epic, real epic. (the ability to progress beyond level 20 adds to that, I suppose)
As for recommending any modules... to be honest, I only recently started trying out various of the single-player modules. Up to this time, I had mostly been playing in DMed games at NWC, or building and DMing myself. Still, from the few that I've played, I can recommend...
The Vethboro Dragon - This module is just short and sweet. A very small storyline, but uses some interesting gimmicks. Most of all, the module can be completed in 2-3 hours, yet have you ending the module with a smile on your face.
Good vs. Evil - An interesting module that lets you play NWN as sort of a RTS.
A Hunt through the Dark - Basically a module where you have to play as a Drow Elf(think the opposite of a good elf). Has good RP options, you can opt to play a good Drow as well. Has a neat storyline, and I'm looking forward to see how the author is going to complete this series. Mental note, although these modules can be played without any of th add-ons, I've heard that the next module will require HotU at least.
The Sinister Secret of Saltmarsh - I played this one online once with a DM, so I can't exactly determine how the SP-version is. However, it was a fun module, and one that I just might DM myself at some point.
Honor among thieves - I've only played this one for a short time, but it seems to be an open-ended module, specifically meant for thief classes. I heard some good things about this one, you might want to check it out.
Witches' Wake - The first official Bioware module that they released for free shortly after NWN(from which I also had the honor of being my first DMed game as a player, while one of Bioware's developers was there as a DM). This one is much more RP-oriented, you actually get no XP for combat at all. It is rather short tho', but : Good news - they recently started working on the sequel once the developer had done his work on Jade Empire(Bioware's X-Box-exclusive Action-RPG), Bad News - You'll most likely have to pay for it once they've set up the Digital Payment. Basically, you'll be able to get official Bioware modules for NWN at a small cost. However, patches and the content that is used in the modules will always be delivered for free.
There are quite a few more modules out there that I would recommend, but they require the add-ons, I've tried to limit the modules here to NWN-only. Finally, I would also recommend checking the
NWVault review page.
The answer is maybe.