I purchased this product as a present for myself for Christmas including the 18-55 IS kit lens. I have owned numerous P&S cameras - Casio, Canon, Nikon, etc, but decided it was finally time to upgrade to a DSLR - and at a great price. I have taken about 500 pictures so far - with flash, with manual controls, in auto mode, pretty much everything already.
The Camera body - very solid build. I had read some reviews which were critical of the use of plastic over metal but I really think that the plastic is great. I'm sure a drop would damage it in some way, but the plastic feels very sturdy and has no flex in the body at all. Every compartment opens and closes tight and with some resistance, which gives a very stable feeling. The buttons all feel great to press. The shutter feels very sturdy and has great feedback when you press it. The camera body is a good size for me. I am taller than average but not giant and my hands are pretty good sized and even the smaller body on this camera (compared to the 40,50d, etc) feels fine. My only complaint is sometimes tiredness which I get in my right pinky finger from the grip on the camera. I'm sure in the coming weeks I'll work this out as I experiment with new ways of holding the camera most comfortably. Overall, the camera body is sturdy and feels very well made.
Features - Wide spread. I am coming from a Canon G9 which already has a pretty full feature set, but the ultimate manual controls on XSi just lets me feel much more connected to this camera. The Auto mode seems to work fine. I'm not experienced with any bigger or fancier DSLR's, so this mode seems fine to me - autofocus, flash and everything. Manual mode allows for the ultimate control of pretty much everything. I love taking nighttime, long exposure shots and the XSi allows for up to 30seconds of exposure or a BULB function. The results are great out of the box, though I'm sure with post processing some of the graininess that results can be cleared up.
Specs - The images are crystal clear with the kit lens compared to my G9. Even though they are both 12MP, the XSi at a 100% crop is so much clearer. I now don't worry about zooming in as far as I can - knowing I will be able to crop out a larger, closer image in the future if I want to. The built in flash is sufficient and has a pretty quick refresh time. I also have a Canon 220Ex which is a bit more powerful (not much though) but does have a much quicker refresh time. In burst mode on the XSi I can shoot twice as long and 1.5x as quick with the 220Ex which could really come in useful. I would invest in an external flash unit but for everyday shooting the built in one is fine. The autofocus is quick in my experience so far and is pretty accurate. It is much quciker than the G9, even in low light. Low light does slow it down a bit, but not bad at all.
Kit Lens (18-55) - As I have said this is my first DSLR so I don't have much knowledge of lenses, but this one is pretty GOOD, not great. The zoom is pretty basic - less than my G9 but wider angle to begin with, which I find more useful. I will eventually invest in a probably-Canon longer range zoom but for now, this is fine to be begin on. It is a quick lens and the Image Stabilizer seems to help (haven;t tried many moving situations yet) so I can't report completely on that. I do miss the focus distances on the manual focus ring (infinity to close, etc) so it is sometimes confusing to see what distance I am focusing at. Overall, a good lens and definitely worth the kit price if you are just starting out.
Battery - The battery is great. I have taken almost 600 shots on the first full charge still, many of which have been flash, and the battery is only down one notch. Obviously this will go down with time, but it seems great.
Complaints:
1. Body size is good but takes some getting used to. not really a complaint, but just saying it will take a while to find a completely comfortable grip.
2. Live view sucks. I love shooting through the eye piece, but in just using live view even for fun, it is bewildering and slow and bad. If you have a tripod it will be fine, but otherwise, do not buy this camera if you MUST have live view. I wanted the XSi because it did have live view, but I now realize I much prefer using the eyepiece. It is nice to know live view is there if I need it, but I cannot really see myself using it more than 1-2% of the time.
3. Battery door almost impossible to open. I don't know why - it could just be mine but I'm thinking it is the way it is designed. I have to use a pencil tip or a butter knife in additon to my finger to slide it open and out.
4. Lack of movie mode - I know, I know - its an SLR. But I have seen that Ashton Kutcher ad for Nikon with their HD movie mode, and I have to say that would be pretty cool to have on here. I have a feeling on the 500D or whatever the new Rebel is, Canon will install that. But I wish this one had it.
Overall - Great beginners camera and even for a moderately experienced user. Only drawbacks are minor ones and for this price point, cannot really even be considered. I've wanted the Rebel since the 300D came out, and I now finally have one and I am in love. Get more detail about Canon Digital Rebel XSi 12.2 MP Digital SLR Camera with EF-S 18-55mm f/3.5-5.6 IS Lens (Black).