I'm gonna focus on this answer for a second - Nikon fans are gonna hate me for saying this, but it's the technical truth. If you want to buy into a system that's more future proof, then your best bet is Canon.
Canon's top lenses are L lenses, they were designed around 35mm film cameras and are fantastic on both crop (Rebel, xxD) bodies and full frame (5D, 1Ds) bodies. Edge to edge you're getting the best quality.
Canon's L lenses are their professional line- Nikon's professional line lenses are all full-frame lenses except the 12-24mm, 10.5mm fisheye and 17-55m. For full-frame bodies, there's the 14-24mm, 16mm fisheye, and 17-35mm as alternatives if you don't want to shoot in DX mode- the D3x (full-frame) in DX mode is 10.5 megapixels- more than enough to justify keeping good non-consumer DX glass around.
As far as "designed for 35mm film," you may be surprised to find that film resolution is generally less than the resolution quality needed for the venerable Nikon D2x -
http://www.diax.nl/pages/Lens_res_uk.html.
Nikon backed itself into a corner with lenses. Right now their top bodies are outperforming Canon on some important issues (noise), but their lenses are the kryptonite. When Digital SLR's came into popularity, we were introduced to crop body sensors. (The CMOS/CCD in the camera is 1.6 times smaller than a 35mm piece of film). Nikon then decided to built a whole new range of lenses for their digital bodies and the DX lens was born. However, DX lenses were designed for a 1.6 crop sensor body. Recently, Nikon released the FX body (full frame) and DX showed some weaknesses on edges, as the lenses weren't designed for full frame optics. The centers were great, but the outsides were not. Canon doesn't have this problem because the L glass was all designed around film, or full frame sensors.
First of all, Canon uses a 1.6x, FX and 1.3x crops, Nikon uses 1.5x and FX. Secondly, Nikon FX bodies have a DX crop mode to allow folks who've purchased DX lenses to continue to use their lenses on the FX bodies if they wish. Thirdly, once again you're comparing a professional lens line with mostly prosumer lenses- I've got about $17,000 in Nikon lenses, and I own exactly *one* DX lens (a Sigma 10-20mm.) Funnily enough, the Canon 10-22mm lens is an EF-S lens (Canon's version of a DX lens.)
It's going to take Nikon several years to pick up the slack created with their lenses. So if you want something more future proof, you'll want to pick Canon mainly for the L glass, should you ever venture in that far.
Nikon doesn't need to pick up any "slack," they continue to offer the following FX lenses (f/2.8 unless otherwise noted)- 14mm, 16mm fish, 20mm, 24mm, 28mm, 35mm/2, 50mm/1.4 (AF-D and AF-S,) 50mm/1.8, 85mm/1.4, 85mm/1.8, 105mm/2, 135mm/2, 180mm, 200mm/2, 300mm, 300mm/4, 400mm, 500mm/4, 600mm/4, 14-24mm, 17-35mm, 18-35mm/3.5-4.5, 24-70mm, 24-120mm/3.5-5.6, 24-85mm, 70-200mm, 70-300mm/4-5.6(IF and G versions,) 80-400mm/4.5-5.6, 80-200, 200-400mm/4, 60mm (D and G versions,) 105mm, 200mm/4 as well as eight manual focus lenses and three perspective control (T/S) lenses.
There are four or five "consumer or prosumer" lenses in that list- two of which are variants of the same lens.
Canon's L series looks like this:
35mm, 50mm/1.2, 85mm/1.2, 135mm/2, 200mm, 200mmIS, 300/4, 300mm, 400mm, 400mm/5.6, 500mm/4, 600mm/4, 800mm/5.6, 16-35mm, 17-40mm, 24-70mm, 24-105mm, 28-300mm, 180mm, 70-200mm, 70-200mm/4, 100-400/4.5-5.6 and two tilt/shift lenses.
And the Nikon guys will now attack this post, but this is the honest truth that I got from one of the best photographers in the world - who ordered an FX body the day they were released, but soon cancelled the order when he learned of the mess Nikon made on the lenses.
Then your "best photographer" is an idiot in real life- if he can't go through the Nikon catalog and ignore all the consumer lenses labeled "DX" then he's going to have as much trouble going through the Canon catalog and not ignoring lenses that have "EF-S" in them.
Yes, I'm attacking this post- but because it's not factually true- Nikon makes forty-five (45) FX compatible lenses- Canon make fifty-three (53) and I'd bet if we took out repeat focal lengths we'd have a difference of about three lenses- none of them more than 1-2mm off in total coverage except the 800mm/5.6 which I don't know any Canon wildlife photogs who shoot with. Nikon also has one additional TC (1.7x.)
Both Canon and Nikon keep their lens lines on their Web sites, so anyone can easily verify what the "honest truth" is. The truth is that both companies offer fairly equivalent lens lines. The major differences for wildlife is that Nikon offer the 200-400mm lens and Canon an 800/5.6 (but Canon doesn't have a lens that touches the MTF of the 400/2.8VR.) For architecture, Canon offer a 17mm T/S and for Wedding folks who can't afford/carry a fast lens, Canon offer the 70-200/4. If you're a niche shooter, then the minuscule differences in lens lines are important, but for most people they're moot.
For folks who aren't going to pony up $2700 for a full-frame camera, lenses like the DX 18-200mm super-zoom as an all-around travel lens on a small DX body make more sense than paying for Canon L or high-end Nikkor glass.