I have 3 small criticisms, but they can be described of most DSLR cameras:
i. I do find that even at 15.1 megapixels, the image can only be enlarged so much (even with RAW). For most of my work, the images don't need to go any bigger. However, if I needed to go larger, I would go with the Canon 5D Mark II with a true 24mm x 36mm image capture sensor, and 21.1 megapixels.
ii. The viewfinder is difficult to see with regard to focus. This is especially true when using wide-angle lenses.
iii. The LCD is next to impossible to view on a sunny day.
What I have purchased on E-Bay to help me when shooting architecture outdoors are:
i. Canon angle finder C with adapter: this is an attachment that goes over the viewfinder eyepiece and magnifies the image 1.25 and 2x. I haven't personally used it (I will when I receive it), but I've read that it's a useful accessory. I'll modify this review when I receive this item and use it.
ii. Delkin pop-up shade pro model: This fits easily over the LCD screen and has 3 sides (top, left and right) to make a small "tent" to shadow the sun from the screen. One part keeps coming off (I've notified Delkin),but for the price it's a great item. The images are still hard to see in daylight, but it's an improvement.
iii. An eyepiece that fits over the viewfinder: I haven't yet received this item, so I'll comment later. However it appears to cover the eye better, so that looking into the viewfinder will allow you a better view.
iv. For architecture, I purchased a 2-directional level (both horizontal and vertical levels are shown. This can also be found on e-Bay , and it's an absolute must when shooting architecture. This fits on to the hot shoe of the camera.
For the price, it's a great camera. Would I recommend it - for sure. However, just as I purchased the T1i, Canon announced that they were coming it with the T2i. You might want to look at someone's review and compare the 2 cameras.
In terms of the features, I don't use most of them. There's always RAW shooting and Photoshop. But overall, the Canon T1i is great.
One other accessory that I would wholeheartedly recommend is the battery grip. Personally, I purchased the Canon model. It was on sale at the time. It holds 2 batteries, and is good for about 600 images, shot both as JPEGs and RAW at maximum file size. This is something that I didn't think I really needed, but since I have it, it's great.
For tabletop and architecture, there's not going to be a problem. But if you go on vacation, you'll shoot lots of pictures. Not having to see when you'll need to change the battery is a great asset with the battery grip.
I've only had the camera for about 4 months, so I'll be updating this review as time goes on.
I hope that this review will help you in the selection of your next camera.