"The grass is always greener..."
Either system is good... Nikon or Canon.
In 2001, when I switched to Canon, it was the only game in town. Canon was the only company offering image stabilization. Anyone who used long teles, like I do, was jumping to Canon.
In addition, Canon is a much, much larger company than Nikon. In 2001 it was clear that the future was going to be digital, and I was more confident that Canon's sheer size would put them at the forefront of R&D. They took the tack of developing and investing in their own sensor manufacture, CMOS while everyone else was still buying CCDs from Kodak and Sony (Nikon still buys from Sony, altho now it's CMOS).
Canon enjoyed about a 5 year lead on everyone else with image stabilization. Similar with CMOS image sensors. Then they were the first to offer a sub-$2000 DSLR (10D, 2004). Then they were the first to offer an "affordable" full frame camera (5D, 2005).
For a good nine or ten years, everyone else was playing catch up, including Nikon.
Fast forward to today, and Nikon has largely caught up and even pulled ahead in a few respects. Now nearly everyone is using CMOS sensors, including Nikon, who had to wait until their supplier developed usable products.
Nikon and Sony both offer full frame cameras (as do some others, or they plan to... Pentax continues to make FF lenses so must have plans, for example). Today one of Sony's FF cameras is sub-$2000.
Right now, Canon still offers the widest lens selection and has better overall system compatibility (learn the difference between Nikkor AF and Nikkor AF-S before you start buying their cameras and lenses). Canon mount is the most universal, allowing a huge range of vintage lenses to be adapted for use on their cameras. Perhaps a bit ironically, one of the few vintage lens lines that can't easily be adapted is Canon's own, old mounting system.
I do think Canon has rested on their laurels a bit... perhaps let off the accelerator pedal a bit while others kept coming full steam (they had to if they wanted to survive, Canon was kicking their collective butts for a lot of years).
There are still ergonomic differences... Be sure to check out the cameras in person before deciding. Canon's "way of doing things" just fit my shooting better. But someone else might feel more comfortable with a Nikon... Or a Sony, or Pentax, or Olympus, or Fuji, or Sigma, or whatever.
Nikon has made some really smart marketing moves... Their D100/200/300 progression identified and met a "pro crop" market that Canon missed entirely until they finally introduced the 7D. Nikon has nicely differentiated themselves with lower resolution, high frame rate full frame cameras. Meanwhile Canon just continued the megapixel race, jamming more and more MP into each new generation of sensor.
Nikon has added some simple features that caught peoples' eye, while Canon was asleep at the switch. Right now an example might be that several Nikon models can bracket as many as nine frames, while Canon still sticks stubbornly with three frames. Nikon also was the first to introduce built-in wireless flash control (tho I still question it... prefer a separate module such as the ST-E2).
Someone showed me another feature recently (I forget whether it was Nikon or Oly, I was working with photographers using both) that I thought was really neat... A zooming histogram. In other words, when you were reviewing an image on the camera's LCD, as you zoomed in the histogram only displays based upon the visible area. I can see where that would be very, very useful when photographing people, or for a white wedding dress, to zoom in and check the histogram on just a select area.
In-camera editing? Well, I can set Picture Styles and shoot JPEGs with my Canon, if I wish. But frankly I am far more likely to keep shooting RAW and just don't see myself doing any real editing until I'm viewing my images on a large, color calibrated computer monitor. It might be nice to be able to crop in-camera... But I don't see much use for anything more than that.
I don't need 51 AF points either. From all I've been able to find out, Nikon AF in the latest models might be a little superior. Canon's most advanced AF still leaves a little to be desired.... But I really don't see any AF system (or metering system, etc.) ever being "perfect". That would make me, the photographer, unnecessary, wouldn't it? Careful what you ask for!
"Innovate or die" certainly appies here... Canon was the DSLR innovator through much of the first ten years of the 21st Century. Everyone else was playing catch up. Now they have caught up, and in some respects others are being more innovative... at the moment. I doubt that will last very long, though.
Does it matter? Well, competition is good for us all. All the DSLRs on the market right now are pretty darned capable of making a great shot. It's more down to the nut behind the camera, than the camera itself. Quality lenses, which all manufacturers offer, are more important than the light capturing box behind them. The camera body is more about conveniences than necessities. So just pick the one you like best and build your system around it... Consider your lens kit first, lay out a comprehensive plan of what you expect to buy and use over time... You might find some systems lacking, Nikon and Canon are the two most complete by a large margin.
It's expensive to switch back and forth, once you are relatively invested in one or the other.