i have 18-70, 50mm prime, 70-300.
Im umming and arring about wether to buy a new camera, im not sure the d70 is working 100%, tbh i think the sensor needs cleaning, afaik i need to send it to nikon for this, and pay £100 or so for the privelige ?
Im kind of swaying towards a 5dmk2, it does full 1080 video which is ideal for my dissy, and amazing features and is FF, and cheaper than the "superior" D700...
You can clean the sensor yourself, cost about 10p a time once you have some pec pads and eclipse fluid.
What makes you think you need a new camera? And I highly doubt changing brands will do anything beneficial to you. There are some specific advantages and disadvantages between Nikon and Canon that only Pros really worry about.
If you want to record 1080p video then buy an HD camcorder...