I am personally really loving the 550D, due note that I am a beginner and you may see things from a different perspective..
One of the reasons I got the camera was also for it's great video mode, and not because I want to make allot of videos. But rather because I believe that that will prevent it from dropping in price quickly. Just in case I decide after a year for example that I don't really like the whole photography-thingy
Apart from that I am loving this camera, the setting are fairly easy to adjust and everything is displayed very clearly on the lcd. Ofcourse the downside to this is that in order to adjust setting you have to stop looking through the viewfinder and at the lcd instead.
The screen also looks great.. I was pretty amazed when I first saw that
And I know how allot of people complain about the 18 mp and how you don't need it, but where is the harm as long as the camera has decent ISO performance (wich it does
And the finnal thing that I really like about this camera is the design.. I don't think this is important to most people (?) but I just really like the canon design..
Since you have been able to play around with it for a bit I guess you know the feel of the camera
To me it does feel a little small when holding it but it doesn't actuallly bother me to much, and if it does I'll just get a battery grip or something..
Anyway if U do decide to go with the 550D, I don't think you will be dissapointed
I don't know allot about nikon and other brand camera's but I guess they are al pretty good too, in fact this may be kind off a silly question because in the end, it's you who decide wich camera is best for YOU, and nobody can correct you on that one!
Good luck finding your camera!