I'll be heading up North to the Himalayas in April + am hoping to get close to some airliners in some time & wish to have a proper UWA Lens along.

My Choices are a bit fancy in their own right

1. Tokina 10-17mm f/3.5-4.5 Fisheye Zoom
Reason i included this is because i got to play with a friends 8mm Fisheye a while back & i again leased it from him in Dubai & thoroughly enjoyed it.
I've read buyers in their post-purchase Review quoting it having near Rectilinear Wide Angle image quality at 16~17mm.
Plus, i've been following this http://www.flickr.com/groups/89315049@N00/pool/ group on Flickr for some time now (got the link while browsing FM forums) and some of the shots i've seen there...................   

2. Tokina 12-24mm F4
Reason i'm contemplating this is due to its marginally greater reach.
Anybody else here using it?

3. Sigma 8-16mm f/4.5-5.6 | Bryan has been very generous in his praises for it.

Both the 10-17 & 8-16 cost about the same ~$670-~700 whereas the 12-24 is in the region of $450

I wouldnt mind buying the 11-16 f2.8 but am leaning more toward these ^ three.
Besides the odd airplane shooting opportunity, this lens may primarily be used for shooting family & the outdoors therefore no specific need as such of a larger aperture.

Your opinions & suggestions are most welcome.

- VJ