The Tokina is quite nice. It is a cheap way to go wide. I like shooting primes, so it was the only real choice for me.
If you check out the Fish Market pics on my web site, most of those were shot with the Tokina 17mm. They were at ISO 1250 at around 1/20-1/50 of a sec. So I doubt they are the sharpest examples. But it is a nice lens and on the D100, any edge problems are nil.
I can send you some shots when I'm back home (in the office right now) of shots I did in my studio of the same person some with the 85mm 1.8 and some with the 50mm 1.8. Overall I feel that the 85mm is the way to go for single portrait shots. If you have more than one person in the shot I suggest the 50mm. The 85mm is just so darn sharp and the bocha is amazing.
Yes I agree, the 85 is the way to go. A 50mm even with the 1.5 factor is to short for good head shots (OK for full length at a push). With the 50 you would be too close to your subject to yield good perspective.
I'm still saving up to expand my glass collection for my D-100, so shoot mostly with a 50mm f/1.4 and a 28-200 f/3.5-5.6. With the zoom I find that I'm mostly setting it at 85mm for head shots, so an 85 is next on my list to buy when I get the money. I like the 50 for full length portraits, but for heads 85 is a comfortable lens for me. The real question for me is whether to buy the f/1.8 or keep saving for the f/1.4 with its legendary Bokeh.
Not to take pictures of one's children, particularly when they are small, is a sign of parental indifference --- Susan Sontag