Canon’s Zoombrowser EX version 6.0 is truly color-managed as far as I can tell, means that the monitor profile is used for conversion and display on screen. Probably there’s a free download somewhere in the support section for their cameras. IF you shoot with a Canon, Raw files are previewed as well, while emulating the in-camera flavor of conversion. There’s a full screen mode, although it is to mention that the software is slow in many aspects.
Windowz’ Picture & Fax viewer as well as their Raw viewer power tool like to convert everything to sRGB for monitor output (at least when I tried the last time), so that there’s easily a discrepancy with a monitor’s de facto given gamut.
Of course, there’s the Adobe range of color-savvy products…