I've had this lens for a few months now, it was my first purchase for my D90 kit and while it's not a cheap lens, it's not expensive either and for what it can do, I can't imagine spending my money better.
The lens equates to a 'normal' view lens on a DX camera (what the eyes see, basically) and so it is a general pupose lens - ok, we can pretty much rule out macro work and long range telephoto shots, but it is just great for everything and I do mean 'everything' in between.
For your money you get f=1.8 glass, that's fast enough for pretty much anyone I reckon, a couple of stops in at most and you've got sharp subjects and lovely dof.
There are forums and discussion sites, chewing the cud over which is the best 'portrait lens', the 35, 50 or 85mm (or indeed the 105mm) and being fairly new to this game, I'm trying to learn from people who speak reason and the best statement I've found so far was in response to this question - 'if you view a particular lens as only having one job, based on its focal length, then you're going to take pretty much average pictures with minimal creativity'. Personally, I've found it's much better to grab a short prime (this one!), run around, get loads of pictures, make your legs do the zooming so you can focus (no pun intended) on composing a great shot and see what happens...and just for the record I have taken some great head and shoulder portraits with this lens.
The only other thing I can add, while I'm on the soap box and handing out free advice, is in relation to people criticising plastic mounts on some of the DX lenses (this one included) and the fact that they apparently break when their camera is banged or dropped. The conclusion that I have come to so far is that it's best not to drop your prized and hard earned posession, as damage will likely ensue. Should you be one of the unfortunates who does treat their camera to a good pasting, surely it is better that the plastic mount breaks (possibly repairable), rather than the expensive glass work, or the camera case, or the internals of the camera....sorry if I sound sarcastic, but I've only been in this game for 6 months and already I'm sick of people bleating about this. If you agree, click the 'useful' button on this review, hopefully, I'm not alone!
Now go and buy the lens, it's great.