Well...
.... needless to say, but you're on a journey where you'll probably ask (eventually) every question in the "the book". So - with that in mind I'll not attempt to go much beyond the initial scope of your queries...
.... on equipment... the first consideration is that Canon currently has 60%+ of the DSLR market share. That translates into Canon having sold more DSLRs annually then all other manufacturers COMBINED. Further explanation may NOT need recanting - that said. But I will go ahead and offer that Canon seems to have been 1st to market with the image sensors producing the CLEANEST images combined with the most powerful sensitivity levels. IE, highest ISO levels WITH super clean images. BUT, that alone is not enough. Canon evolved effective image processing ICs. These components seem to be exclusive to Canon - as opposed to other companies who have purchased their components from one another to achieve competitive economies of scale in a timely fasshion. Technology advances quickly in the market-place. AND - since Canon has the edge in volume and technology - that gave them the edge in price... IMHO.
Now - on the price thing - some would argue ... so WHERE is the price advantage for us consumers? Well... Canon has a huge R&D committment. I can't quote numbers - but I read recently of what they're doing and it seems to me they are geared to compete against the entire industry to maintain their edges.
Another arguable area of strength - their lense arsenal. The adage that all the lense barrels at professionally shot public events are shot with the white barreled lenses of canon - seems true. Professionals choose Canon because Canon lenses seem to exhibit more advanced designs and lense compositions. Also, their designs have a reputation for delivering "the goods" in sometimes difficult conditions. Of course... I am not a true professional... nor does anyone have to be one to offer a qualified opinion.
From where I sit - Canon OR NIkon would give excellent images with all the creative pleasure conceivable... up to 11x14 or slightly larger prints. Of course, I used to print larger sizes with less than half the pixels (3.1MP) and I was happy. Just goes to show ignorance is bliss!
So - I think the Nikon will FEEL and HANDLE better initially. But after slight consideration you might notice the Nikons have slightly slower and less sophisticated focusing systems. Plaso, Nikon does not make a fulll frame sensor DSLR... Canon sells 2! Plus - they make and sell a mid sized sensor DSLR specialized for rapid bursts for professionals or advanced amaturs.
As for the glass... I used to be a NIKON SNOB - but now I'm a quiet Canon enthusiast. I would be pleased if Nikon were more competitive - but it is off a fraction of a notch... and will stay that way until something dramatic happens.
I think the 350 is undersized for my hands. It may be very conmfortable for you though. It is a ton of DSLR for the money though. AND, I don't like the cheap mode dial on it.... it drives me nuts and I could not buy it.
Another final comment than I have to go... my daughter has her 1st swim meet today and I am the volunteer team photographer! And that is... the 350XT may be on the cusp of being replaced by a new model. Canon seems to replace their models every 18-20 months like clock work. SO - it this occurs you might want to wait for the next model to get the "improvements" or get a bigger discount on a recently discontinued model that used to be the "best in it's class". I use an old 10D that uised to be the best in its' class too... and I am supremely happy with it.
Hope this helps... if you could volunteer more about your skill level and ambitions/needs than perhaps you'll get useful and focused answers (unlike my general dribble here).
I hear ya Mickey88...
