There is a blog site dedicated to the D90
- check it out! -
http://nikond90lab.blogspot.com/

You could break the lock on Canon APS-C lenses so they will mount on full frame body, but you can break mirror that way and you will loose something you really could not afford with Canon quality and that is your warranty ;)
The idea behind Canon different mount for APS-C cameras was to be able to make lens rear nodal point glass closer to the sensor plane and that could give you better image quality with wider lenses, and I must say that this idea was actually correct.
On the other hand almost all Nikon F mount lenses ever made could be used on any Nikon body, it is just that mechanical AF will not work on the body without internal AF motor but you could use them in manual focus mode. As all lenses are replaced by an AF-S version internal focus motor will eventually disappear from Nikon bodies and that will make them cheaper and more reliable.
Next thing that is being moved into the lenses is aperture drive so that all mechanical drives between lens and camera will be removed in the future.

Yeah Canon lenses are not always compatible. Ken Rockwell, if I can use him as an example, talks about the "great Canon Devide of 1986". This is when Canon changed their lens mount. The EOS mount cameras and lenses are incompatible with anything prior to that divide. Even within the EOS mount there are other issues; unlike Nikon, Canon's full frame cameras will not work at all with the lenses designed for their version of DX (cropped sensor). At least Nikon gives you the center part of the sensor so you're not completely out of luck. Then there's the EF and some other designation within the EOS mount. All kinds of issues with Canon IMO.

try to connect old canon lens to some of the new bodies and You will see why... (they will not work), as the "internal motor" is absent. Nikon OTOH has one of the best back compatibility in lenses on the market, as You still can use on any serious Nikon body almost all lenses they ever produced, even the ones dated to 1950's. As for the cheap cameras, it's a way of making money. You pay less for camera body, but need to use new lenses with build in ultrasonic motor - pretty much like with printers, You buy a cheap one and pay a lot of money for drum/ink/toner or You buy more expensive one and save on all replacement stuffs.

I dont understand why nikon comes up with bodies with and without internal motors and different kinds of lenses that work only on selected bodies. Why cant nikon come up with uniformity like the canon counterparts? In canon, the motors are absent in the bodies and are present in the lens.

I think you will be glad you opted for the D90... happy shooting!

haha yes welcome to the D90 club

Hurray! Join the club.

Thanks for all your comments, they were really helpful. I finally pulled the trigger and ordered my first DSLR. A D90! Should arrive in 3 days!

Dear allenh lenses with built in motor were invented for the first Nikon AF camera F2AF back in 80s, and can be used on most Nikon AF SLRs and all DSLRs and are actually faster to focus than build in motor.

If budget's not a problem I would wholeheartedly suggest the D90 over the D5000. The viewfinder alone is worth the extra money, and you WILL use that.

Thanks for the comments. I'm still not sure... I'll have to think about it. I haven't seen the D5000 yet to compare the size with the D90. Although budget is not a problem, I don't want to pay for something I wont use...

Can someone clear this up for me - the lenses with built-in motors (for the D40/60), can they be used on cameras with built-n motors (D90, etc)?

D5000 is actually a bit higher and deeper that D90, and D90 is just a bit wider and heavier than D5000, so I really could not say the size difference, probably someone should calculate volume or something.
On the other hand D5000 has full plastic body, and D90 has aluminum one covered with plastic and will give you much more control buttons and top LCD screen if you need them.
As far as I can say D90 is for someone willing to experiment and try to be a bit more creative, while D5000 is for people just willing to shot and not spend much time thinking.
But that is just my humble opinion.

I don't think the D5000 is much smaller than the D90 anyway. If you really want small you should get the D40 or the D60. But yeah, like the other members, we would recommend the D90 if price was not an issue.

the viewfinder on the D5000 is about as pathetic as the D40/60 series. . the menu is slick though, nice new fonts and cool back screen, and not enough can be said about that live view screen - very cool shots could be had with that - looking forward to it on a D400, contrary to my thoughts before. . .

Except new third-party lenses like Tamron and Tokina (apart from Sigma's HSM).

seba316 - as for Your question, if You are not using old lenses, than it shouldn't be a problem for You, as all new lenses are equipped with AF-S.

What tai said

I'm sure you can be happy with either, but I think the D90 gets you a lot for the extra money. Not only the focusing motor, but a vastly superior viewfinder, and nicer screen, though it doesn't articulate. You very well may come to want to buy AF (as opposed to AFS) lenses, as you can often save a lot of money by buying AF over AF-S. Depending on the lenses you want to buy, you could make back the money lost by going with the D90 in lens savings very quickly.

Hi, I was planning to get the D90 until I heard about the D5000. This is going to be my first DSLR so I'm looking for something easy to use. I played with the D90 and found it a bit big. The D5000 appears to be a better choice since it is smaller and cheaper.

How important is the internal focusing motor? Of course, I don't have any old lenses. Thanks.