The Canon and Nikons both use lens-based stabilization - if you are looking for in-body stabilization, that's the realm of Sony, Pentax, and Olympus.
However, just to throw out a little aside - comparing directly lens-to-lens, surprisingly the stabilized lenses from Canon and Nikon aren't necessarily more expensive than the non-stabilized equivalents for Sony and Pentax. Cost for new lenses isn't really any advantage one way or the other. That said, in-body can still have some nice perks, like buying used lenses cheap, or more specifically buying older lenses, cheap lenses, or primes that aren't offered with lens stabilization, and still getting optical stabilization with them.
All the cameras you listed are fine cameras...though a wee bit different. The Canon is an entry model, well featured, and plenty capable...the nikon is an advanced entry model which will have a few faster performance specs...but is also an older model close to replacement...and the Sony is a brand new model with a new type of mirror system that stays fixed while shooting and uses main sensor to provide the view through an electronic viewfinder or LCD. All are probably pretty close to eachother in overall image quality, and higher ISO performance...just understand the difference of how each works...and see if you can handle the cameras and decide what you like the feel of in your hands.
Also, you might consider some other models in the Sony line if you aren't as interested in the electronic viewfinder or if you don't like the much more compact body of that camera - the Sony A500 and 550 are just as capable and fast performance-wise, being roughly equivalent to the D90 and about the same age, so they are on good sale prices...they have similar high ISO performance, fast 5fps and 7fps burst rates, and huge batteries that will last for 1000+ shots on a charge. And the new A580 camera is the replacement for the A550, just debuting in the next month or so...it has a few more beefed up features and is a nice evolutionary upgrade over the A550 model.
Just some extra stuff to consider!
Sony DSLR-A68 / Sony 18-250mm / Minolta 50mm F1.7 / Tamron 150-600mm / Minolta 300mm F4 APO
Sony A6300 / 18-55mm F3.5-5.6 / 55-210mm F4-6.3 / 10-18mm F4 / 35mm F1.8 / 16mm F2.8 / FE70-200mm F4 G OSS / FE70-300mm F4.5-5.6 G OSS / via manual adapter, lots of Pentax K mount, Konica K/AR mount, and Leica M mount manual lenses