A mint in box demo Sigma 15-30mm f3.5-4.5 popped up on ebay from a reputable seller... total was about $275 shipped after 8% off with Bing Cashback... pulled the trigger. Hopefully I like it, but if I'm not happy then its much easier to find a Nikon 18-35, and won't be hard to sell the Sigma since demand seems to be greater than supply.

15mm is gonna be wiiiide on full frame, probably wont go full lock on that too often. Just hope its sharp enough to keep me happy. It has mostly very favorable reviews, but sounds like poor quality control so not all copies are good.

Trying to decide what I want next. I basically only shoot with my 50 1.4 now.. but I'd like something wider. No idea what, though.

How wide?

There's the:
35/2
35/1.4
28/1.8
24/1.4

All of which are good

a used 17-40L is probably the cheaper than the above options.

Thanks, I'll check out all of those. Really taking my time picking a new lens.

Going rate for a used 17-40 f/4L is about $600-650. I've haven't seen anything lower than $600.

The 28 f/1.8 you can probably get for $400-450; if not less. Depends on the date code and condition.

The 35 1.4 is $1,000+.

The other's I'm not so sure about, but those 2 lenses I've been shopping around for, so I know off hand.

If you can fork it over for one of the 24/1.4, the version one is cheaper and you have to look at like 3 of Bob's pictures to see how great it can be in the right hands. Plus if you ever move to full frame it'll be a nice different focal than the 50, and it'll be good on the crop too.
If that's too much I say 28/1.8.

if you want to do landscapes 10-22mm hands down. the 17-40 is also nice but not the greatest focal zoom, unless you went full frame. both are around 750-900

Bob makes me want to sell all my zooms for primes. Unfortunately I know its not quite that simple.

p.s. got the Sigma 15-30mm today, and initial impressions are really good. It was described as a demo and looks to be... could have told me it was brand new and I would have believed it. Just took a couple shots around the house but it looks like it makes some nice images, and is a really fun focal length.