Sounds like it's right.
I'm 6', 31 inch trouser inseam, so, I should fit a 58cm frame also.
I am most comfortable on a 57cm frame, but a 58cm can be made to work comfortably. 54cm would be a small cockpit for six footer, unless you had really short arms.
It's more than just the frame size.
Standover, top tube length, reach to the bars, and crank length can all come into play.
Where does it feel too big?

http://www.peterwhitecycles.com/fitting.htm
http://bicycling.about.com/od/howtor...Frame_size.htm
http://veloweb.ca/bike-fit/