Interesting question! USD $10,000 is a LOT of money. It depends really where you live and whether you travel lots.
For me I would prolly blow it on a Canon EF 600mm f4 IS USM lens, 1.4x and 2x II teleconverters, and the upcoming 1D MkIII DSLR body. Any spare cash would prolly be thrown into a good solid Gitzo CF tripod, Wimberley II head and CF cards, bags and the like.
Explaining my choices:-
Canon EF 600mm f4 IS USM - Lets face it, when you are shooting wild birds you need all the reach you can get, I find myself cropping my pics about 80% of the time. The Canon 600mm is a hefty piece of kit but it gives you the reach and the image quality in spades. Coupled with the 1.4x TC the lens becomes an 840mm f5.6 still with excellent image quality - IMO the perfect focal length for shy birds or small songbirds. The IQ is undisputed, there is something magical about big lenses like the 600mm that can 'pull' the subject in and smoothen the background to make the subject 'pop'. Really a magical lens. If you feel the weight and size is too much for you, or if you travel frequently, the Canon 500mm f4 IS gives the same performance at a slightly lower cost and in a much more manageable package (i.e. smaller and lighter)
Canon EOS 1D MkIII - This is prolly many a bird photographer's dream camera...10 megapixels coupled with an awesome fast AF tracking system, 10 frames per second, low noise at high ISO, in addition to all the bells and whistles. The only downside is perhaps the size/weight of the camera and the 1.3x crop factor (my personal preference is for a 1.6x crop body with the features of the 1 series). But still this camera is awesome for what it can do, especially for action and flight shots.
Canon 1.4x / 2x Mk II teleconverters - These teleconverters (especially the 1.4x) are essential pieces of kit for any bird photographer because they extend the length of your lenses by a factor of 1.4 times or 2 times. Very handy when you need the additional reach. With the 1.4x you only lose one stop of light while maintaining practically almost the same image quality as with the bare lens used by itself.
Gitzo CF tripod & Wimberley Head II - This will prolly take up the remainder of the funds (assuming there is still any left over) - never underestimate the importance of a solid support - especially with a long lens like the 600. The full wimberley head is incredible in that it makes such a big lens almost weightless and perfectly balanced on the tripod...and the ease of operating means it can also be used to track fast action and follow birds in flight.
Now I only wish I had that kind of money to blow!