I had to dust off image manipulation skills and a program I haven't used in over two years to slap together this rough comparison of the skyline. With time and practice, I probably could have put together something a bit more polished and properly aligned, but fuggit - it's a Saturday morning project born of boredom. I'm not exactly a skilled photographer, but I do like to capture images with the tools I have available.
The top image was shot with a Sony Ericsson w300i phone. The bottom was taken with a Sony Cybershot DSC-W210. The top image was captured in the phone's panorama mode, and almost certainly from a slightly different spot on the balcony from the bottom image, which contributes to some of the misalignment. I tried to brighten the bottom shot to reduce the lighting differences and make picking out differences a bit easier. I think the phone camera tended to vertically stretch images; I tried to correct for that as well. These images face west-southwest; north is to the right, south to the left.
The following exploration is a bit of a guess. If I incorrectly identify any of these structures, or you are able to put names to buildings I missed or couldn't identify, let me know and I'll update this post with your information.
The most drastic changes seem to be around Regent Park, visible on the left side of the image, where towers and low-rise complexes are being replaced by high-rises. There are other towers visible in that direction beyond Regent Park, between the core and the waterfront; condos have risen like weeds over the years. Many of the new structures are condominium complexes.
Around the core, the new Trump building is visible just north of First Canadian Place, the second-tallest building in Canada, which is just to the right of the CN Tower in these images. There is at least one more tall new tower farther to the right of which I cannot identify, though I think it may be an office/condo complex on Queen St. W. Just left of centre is the northernmost tower of the Eaton Centre, with the back of City Hall immediately to its left. The central tower of the Centre is the next tall tower to the left of City Hall; you can see what may be a new structure beyond it in the 2012 image.
Continuing northward, the new College Park construction and another new building surround a smokestack clearly visible in the 2008 image. More new towers can be seen around and beyond the St. Jamestown housing complex on the right side, including a tower at the extreme right that I believe is on the southwest corner of Bay and Wellesley.
Beyond the edges of the image, several new buildings can be seen in the direction of the Distillery District to the south, and around Yonge and Bloor to the north. At least one construction derrick visible in the 2008 image; if there are more, I haven't been able to spot them through the low resolution and sketchy cell phone CCD quality. Numerous derricks can be spotted across the 2012 image, harbingers of yet more skyline changes to come.