#2. "RE: D5000 vs Canon Rebel T1i" In response to Reply # 0
El Sobrante, US
Something else to consider: I'm pretty sure the AE-1 used FD mount lenses, which would not be compatible with the modern EOS bodies. So if you go with the Rebel, you will need all new lenses. You might want to have your wife handle copies of each camera. When I switched from film to digital, I looked at every brand available in my price range and found that the Nikons were much more comfortable for me to hold and use. All of the Canons below the 20D felt too cramped. Your wife might find otherwise.
#3. "RE: D5000 vs Canon Rebel T1i" In response to Reply # 0
Welcome to Nikonians! When Canon introduced their new EOS line of autofocus cameras in 1988 they did something that no other maufacturer had done. They totally abandoned their previous lenses. The FD mount lenses used on their manual focus cameras simply would not fit on the new EOS cameras at all. Not only was the mount coupling different, but the "flange to focal plane" distance was longer (44mm vs 42mm), so even if an adapter was made which allowed an FD lens to mecanically couple to the EOS mount, the lens wouldn't focus to infinity. To allow the lens to focus to infinity, the flange of the FD lens would have to be 2mm inside the EOS body. So her Canon lenses will not work on an EOS Digital Rebel T1i.
#5. "RE: D5000 vs Canon Rebel T1i" In response to Reply # 4
St Petersburg, RU
In real use the differences come out more, not just static tests of individual specs. AF performance and real world low light capabilities are noticeably better with the D5000. The only downside really is lack of a focusing motor so older lenses that require an external focusing motor will not AF on the d500 but will easily work NF. If she ignores the specs and just holds both she would pick the Nikon because it feels better, not like a toy which is a common complaint about Rebels. When I bought my D90, it was newly released. Since it was out of my price range I had not even looked at the D90. The feature list of the 450D/Xsi seemed impressive and it was reasonably priced. I went to a store that had both brands and immediately was unimpressed with the size, fit in my hand and flimsiness of the Xsi. I picked up the D90 and immediately knew it was for me, before I even knew its specs. Boy, am I glad I tried them both, since that time I have discovered the D90 is even more competent performer than I could have hoped for. My friends who have similar Canons are envious. Years ago I shot extensively with a Canon A1 which I loved. All the nice lenses I had became obsolete overnight however. There is nothing in common between her older Canon and the Rebel so she will would not have an advantage of being a prior Canon shooter when trying to master her new camera. Stan St Petersburg Russia