I decided to go Canon, as my first digital camera was a PowerShot SD400, and I just loved its image quality and color. I never thought digital images (at such low resolution) could look that good, even when printed. So, I figured I should go with another Canon as it's more likely to give me the image quality I desired. I bought the 30D as I was looking for a "non-plastic" body, with a budget of around $1000.
I also picked up a 24-70L, because I also thought I should spend about $1k on the lens. Looking back, I didn't really know much about how good of a lens that was, or any clue on crop factor, other lenses, etc. Just got lucked out I guess. I also read I should get a flash for indoor bounce photos, so I got a 430EX at the same time too.
I was very happy with that setup for about a year, then as I learned more about other lenses and cameras, I decided to go full-frame. I too was waiting for 5Dmk2 for the longest time, but gave up and decided to get a 1DsMk2 used instead, then sold my 30D. I picked up a few more lenses since, a 530EX II, etc. and been very happy with this setup so far.
I most likely not to switch to Nikon or anything else, unless Canon abandons EF mount some day (and I'm sure it will!). I'll probably give this camera to my kids... although their camera phone will probably take better pictures by then.