The Very Large Array has been doing a survey of HI - atomic hydrogen emission - in nearby galaxies.
The resulting data is pretty amazing.
Collage of the HI images from NRAO newsletter page 3 (pdf)
Note the range in morphology, and the range in scale - the images have been scales to match the best estimated physical sizes of the galaxies. Dwarf galaxies really are little!
Combining multiwavelength observations reveals more info, like infrared images from Spitzer and ultra-violet images from GALEX.
Further, the radio data has high precision velocity information - high spatial and velocity resolution - so the HI maps provide a good quantitative probe of the galaxies' dark matter haloes, especially at large radii.
M81 publicity images - from F. Walter NRAO combining HI radio data with near IR and mid IR Spitzer data.
The near IR data traces dust, the 8 microns is a good tracer of polyaromatic hydrocarbons.
The far-IR flux is a tracer of highly obscured star formation.
