I've talked to several faculty at my radiology department and they seem to agree that the difference between top ten programs are pretty small. So I thought I would post their opinions on the top tier programs.
First Tier: MIR, MGH, Penn, Duke, Stanford, UCSF, Hopkins, BWH, Michigan
(These nine will show up unanimously on everyone's "top 10" list and there really isn't a huge difference between them.)
Second Tier: UCLA, University of Washington, University of Chicago, Northwestern, Cornell, Columbia, NYU, Mayo
(These eight will show up on some people's "top 10" list and are still amazing programs)
Third Tier: BID, UNC, Indiana, Minnesota, Emory, Vanderbilt, UTSW, Wake Forest, Jefferson, Iowa, UVA, UCSD (I know I'll get a lot of flack for putting this as third tier, but it is a rising program. It is still small and while recognized on the West Coast, hasn't gained a "National" reputation that the programs in the first two tiers has. Also they did not fill last year, which is something that would rarely happen to programs in the first two tiers)
(Collectively, these programs are known to be very strong programs within their region, tend to attract candidates from their geographical region. They may in fact be better or equivalent to some of the second tier programs, but do not have the "National" reputation of the first or second tier programs.)