Selling in favour of upgrading to 7D not 60D, 50D to 60D is it an upgrade?? subjective. Definitely a better choice than selling 50D to downgrade to a 550D, as 550D is an entry level and 50D is a semi-pro. Though it is usual that the newer camera to get better spec than the older one, like the 19 focus points of 7D to that of 5D2 but is does not mean selling 5D2 for 7D is an upgrade or 5D2 cannot be considered an upgrade for older 1D MKIII.
I think most of the specs upgrade are quite predictable and expected, such as 18mp, iso 6400, etc.
I am actually excited over some of the good features, such as articulating LCD, the lock on the dial like K-7, the sexy curve, uses LP-E6 battery (that mean another new battery grip

) and mostly the new all-in-one multi-controller lot easier now.
However, I am quite disappointed that xxD has now been downgraded to D90 replacement competition, instead of the previous D300 competition with 50D. I heard the D90 replacement is going to be magnesium alloy now ... ha ha .. what an irony.
Frankly the 60D spec seems to has shifted downward (not referring to the upgraded specs as it is typical of refresh for newer model to have the latest specs, like 500D vs 550D),e.g.
1. 50D used to have 2 custom mode C1 and C2, newer 7D and 5D2 has three C1, C2 and C3, new 60D is down to the same as 550D one just "C".
2. Continuous shooting 5.3 fps vs 50D 6.5 fps. Well this is something not many users used but it go to demonstrate the positioning of this product now more of a serious amateur vs a semi-pro camera.
3. CF flash which is shared format amount the semi-pro and pro body like 1D, 5D and 7D, old 50D. 60D is SD card now.
4. Plastic body instead of 50D magnesium alloy body

Wonder is it still weather and dust resistant like 50D???
I guess we need to wait and see, but well the good news maybe my 50D value probably will not drop much further or too badly now.