Now this is cool.
A group at RIKEN in Japan have just published a study (subscription required) on visualizing, for the first time in 3D, human chromosomes using coherent x-ray diffraction. Coherent x-ray diffraction (as opposed to your regular old diffraction) utilizes, you guessed it, coherence in the x-ray wavefront. The phase differences of the exiting (scattered) x-rays when they hit a CCD camera behind the object of interest can be used to "map" a three dimensional image of that object's electron density. The setup requires no lenses, and can be used to probe objects as thick as a human chromosome - something electron tomography isn't capable of achieving. Additionally, the method has a resolution of about 120 nm, among the highest in 3D mapping of this general sort.
And here, the neatest part about the whole thing (aside from the fact that physics can be - and is - used toward the betterment of humankind): the picture!
Yoshinori Nishino, Yukio Takahashi, Naoko Imamoto, Tetsuya Ishikawa, Kazuhiro Maeshima (2009). Three-Dimensional Visualization of a Human Chromosome Using Coherent X-Ray Diffraction Physical Review Letters, 102 (1) DOI: 10.1103/PhysRevLett.102.018101