Canon 300 f4 £1095 ... Nikon 300 f4 £975
Canon 300 f2.8 £5500 ... Nikon 300 f2.8 £4000 (The previous Canon was £4000 but talking to a guy last weekend they were no longer available)
Canon 500 f4 £8500 ... Nikon 500 f4 £5700 (Again this is the latest offering from Canon the previous model was close to the Nikon)
Canon 600 f4 £7100 ... Nikon 600 f4 £6700 (That is if the Canon is still available the new one is £10000)
Prices from camera price buster, I dare say the new Canon stuff will stabilise nearer to the Nikon stuff once the early adopter rush slows down.
So fair to say price wise there is nothing in it really, probably find that there are more used Canon lenses out their due to there dominance in the market a few years back, plus those wishing to switch to the latest and greatest new lenses.
The best thing the OP can do is go to a shop and try a couple of bodies in his price range, and get the one that feels the most comfortable, both Nikon and Canon make top quality bodies and optics, he will not go wrong with either.
To try and rate one better than the other will always see a bias depending on the system being used by the poster, or the number of adds placed by one or the other in any particular magazine carrying a review of said products.
The individuals ability, or lack of, will have a far greater influence on the image quality than if they are using Nikon or Canon.