Are you willing to lug around the T1i everywhere, they are pretty bulky. Also, you'd have to buy another lenses to even get close to the zooming distance of the FZ100. It's focal length is from 25mm to zooming all the way to 600mm. The T1i's kit lens does from 29mm to 88mm. Your FZ100 zooms almost 7 times as far. To get close to that distance you could get the Canon 70-300mm IS USM, which would give you a zoom up to 480mm but will cost you another $550.
If you don't want the bulk of a DSLR and don't mind losing the long zooming capability then you could look at a Canon G11 or S90.
Yesterday,I purchased a Panasonic DMC FZ 100 based upon the recommendation of the salesperson. I had gone to the store to purchase the Nikon Coolpix P100 as last year I purchased the Nikon CoolpixP90 and toward the beginning of this year the photos looked grainy compared to how they looked when I first purchased the camera. My son recommended I purchase the Canon Rebel EOS Tli as that is the camera he uses and he says it takes great pictures. Now my question is should I return the camera I purchased and get one of these other ones or is the Panasonic DMC FZ100 worth keeping? Any advice would be greatly appreciated.