So you did it? Congrats!
$800 for a Tamron lens sounds a bit ...hm...much to me
and maybe you should ask yourself if you really need a fast f:2.8 lense,
as your (virtual) filmspeed starts with ISO 200 anyway. (AFAIK)

The new Tokina 2.8/28-70 SV got a good review here in a Fotomag.
It's about Euro 300 here and should be available soon.(even sooner in the US)

If a fast lens isn't the issue, I'm very pleased with my Nikkor 3.5 -4.5 /28-105 AFD,
though I don't know how it performs on a DSLR. (should cost about $400)

You should also consider the 1.5 factor for focal length, e.g. a 28-70 mm lens
will work like a 42 - 105 mm on your D100.

You'll find a lot of lens reviews here:

http://www.naturfotograf.com/lens_surv.html

http://www.photozone.de/bindex2.html

http://www.nikonlinks.com/

hope that helps
Thomas