I'm switching from a canon 10d to the Nikon. I've had pretty good results with a Sigma 10-20mm on the Canon but I'd really like to cut down the number of shots without sacrificing clarity. I tried the new Sigma 4.5mm f2.8 full circle fisheye and, in my opinion, it looks like crap. I was thinking about the Sigma 8mm f3.5 which it seems would at least use the whole sensor and also the Nikon 10.5mm although I'm not thrilled about it being a fixed aperture.  
 
Also, Badders, if you read this (and I know you will) I saw you mentioned somewhere about cross-mounting the Manfrotto 303SPH to shoot straight down. Can you elaborate on that a bit? Are you talking about putting it on a head and flipping it 90 degrees? Sorry to ask here, but I couldn't locate that post right away...
 
Thanks everyone!

Get the Nikon 10.5mm for max quality. Get the Sigma 8mm f/3.5 for good quality in least number of shots. Not sure on your comment about "fixed aperture". Both these lenses have adjustable apertures.
 
Bogen Imaging are producing a video showing how to use the Manfrotto pano heads with me demonstrating.... (knew I should have combed my hair...) We were using the new 055XProB with it's 90 deg upper column arm, so I set the arm at 90 degs and mounted a 303SPH with a D200/Nikon 10.5mm locked down and pointing towards the nadir.
 
Everything was 100% stable and I think a perfect solution for taking nadir shots.

Hi lair!
 
If you opt for the 10.5 route you will not be disappointed... and I would strongly recommend the DxO software ( http://www.dxo.com ) as part of your imaging/pano workflow. In particular the "Deblur/Lens Softness" correction alone is worth the price of admission. This Deblur correction is different than UnSharp Masking (USM). Think of it as showing the true accutance of your camera/lens instead of popping the contrast such as USM does... so no halos and is very scalable - i.e. this correction works at various resolutions (Deblur applied to the full res pano spherical, then change its size as desired) unlike USM which should be applied at the final stage. This is not to say USM doesn't have its place - I sometimes use it in localized areas; but DxO's Deblur feature is a huge time saver to say the least as it is applied globally without the artifacts of a global USM.
 
Here are some example images of various resolutions from the 10.5mm - all derived from the same pano image (i.e. the scalability factor), and no USM is used for any of these images, just DxO's Deblur on the full res version.
 
Keep in mind that the "Detail" image at the bottom of the URL/page link just above comes from the near edge of the 10.5's full frame fisheye image - quite remarkable.

Thanks for the response guys! Sounds like the Nikon is obviously what I'm looking for.  
Badders - I was mistaken about the fixed aperture. I was talking about the Sunex lens with someone and I think it carried over from that conversation. I can't wait to see that Bogen video (messy hair and all). I use the 303SPH and it kills me to do those nadir shots handheld.
Jim - Those shots are amazing. The detail is incredible - especially under those lighting conditions. How did the shot look before DXO did its thing? I will be downloading their demos and giving it a go.
 
Thanks again, guys...

Hi lair!
 
See a comparison of Photoshop CS2 vs. DxO here.
 
This image detail is from the same pano image that I used as an example in my last post. The crop detail, as shown in the link referenced just above, is from the glasses on the table.

That is amazing. No comparison. You'd think the Adobe crew would be all over that. The Enfuse sample is very cool, too. I have yet to get into any kind of HDR imaging - and I need to because I often have to compromise on my exposures. Thanks again, Jim.

Hi Lair!
 
"That is amazing. No comparison. You'd think the Adobe crew would be all over that."

But that's why there are plug-ins (DxO works as a plug-in as well as stand alone)... to extend Photoshop's capabilities - and Adobe does not have to re-invent the wheel.
 
Possibly CS3 can do a better job? (Don't own it.)
 
My feeling - why compete against excellence when PS is served so well by these third party apps?
 
All my conversions in DxO are to DNG - so I can use the PS RAW engine to even greater effect.