We all have wishful thoughts. Instead of looking at what we have been blessed with, we often look at what we lack. Soon after I first bought my D90 SLR two years ago, I often had wishful thoughts about other cameras. I wasn't 100% happy or contented, until I learned to appreciate my camera for what it can do, and not what it cannot do.
I must admit there are moments when I wished I had a different camera. I've always had this feeling that Canon's rendering of colour would suit my taste better. At other times I wished I had gone straight into buying a full frame SLR, such as the D700. Of course, that would have cost 3-4 times more than the D90. The feeling of making the wrong choice of camera has been exacerbated by several important points in my photography life.
The first was White Balance control. Buying the D90, I misled myself into thinking that I would achieve perfect WB. When that didn't happen, I blamed the camera. Now I realize that no camera can give you perfect WB. Not even the top end ones. I have made my peace with WB control.
Next was exposure control. Some cameras actually gives a more pleasing exposure when shot in semi-auto mode. I was not very happy with the D90 in this respect. Until now. I have learned that many seasoned photographers use the exposure compensation button all the time. I have learned to do the same myself, so this D90 nuance doesn't bother me anymore.
Of course, the APS-C sensor will still have the 1.5 crop factor, no matter what. That cannot be helped. I still cannot make full use of wide angle lens, nor get the shallow depth of field, nor use very high ISO, such as can be achieved with a full frame SLR. However, the D90 has stood up well and I am beginning to appreciate it for what it can do. That, I think, is the most important lesson in my photography journey. I have stopped imagining I could shoot better pictures by getting a better camera (and I know that's a false proposition). Instead, I now focus on what I can do with my D90 (and I know there's still lots more room to grow!).