Ok I have a plan.....
Get the camera you pointed out to me. From what you're telling me it will be more camera than you'll be ready to handle right off the bat. But alas, now is not the time to worry cuz the more you use it the easier it will become. You will love your new camera.
Here's my part of the plan...
With the dough ( no pun intended ) you saved you will need to buy a Compact Flash memory card. I recommend nothing smaller than a 8 gig card. I own a few of these and they are fast enough for my needs.
SanDisk | 8GB Ultra II CompactFlash Card | SDCFH-008G-A11 | B&H
Now part 2 of my plan....
Take some of your cash and buy this lens. It's the best 100 bucks you'll ever spend on a prime lens especially since you wanna shoot night stuff. I've owned two of those and I'll tell you despite it's cost it's an amazing lens. 50mm is a short range but for shooting buildings you can get close enough to crop what you want. It's great for indoor stuff as well. Note the 1.8f stop.
Canon | Normal EF 50mm f/1.8 II Autofocus Lens | 2514A002 | B&H
Part 3... get a bloody tri-pod. I can't emphasize that enough. It will do you a world of good. No recommendations from me though cuz that's a personal choice. I spent $600 on mine because of the heavy lens I use. :eek