For radar imagery, I use both GRLevel2 and GRLevel3. Full trial versions are available for immediate download at http://www.grlevelx.com/. After 21 days I believe you'll be asked to make a decision as to whether or not you wish to purchase the programs.
GRLevel2 displays reflectivity and velocity data in a higher resolution than GRLevel3. It also offers a feature where you can take a "slice" through a storm and display it in the vertical, in 3d-like fashion.
GRLevel2 Reflectivity Image
GRLevel2 Cross-Section "3D" Image
GRLevel2 Storm Relative Velocity Image
GRLevel3 shows not only reflectivity and velocity data (although in slightly lower resolution compared to GRLevel2), but also other "derived" data such as storm tops, vertically integrated liquid (VIL - a scientific and fancy way to pick out likely hail cores), 1 hour, 3 hour and storm total precipitation estimates, etc. It also displays all of the algorithms built into the NEXRAD system, such as mesocylone and tornado vortex signature plots, hail size estimates, storm tracks, etc.
GRLevel3 Split Screen Display
Reflectivity on the left, VIL on the right.
Lightning strikes, mesocyclone & hail overlays also shown.
I find that I use both programs about equally during a severe weather situation. They both will also display all active warnings, storm reports, spotter/chaser location data, etc. Both programs also use shapefiles and placefiles which allow you to add personal locations, roads, waterways, current conditions and any number of other snazzy features.
Once you have purchased GRLevel2 and/or 3, most of the data are then downloaded and ingested into the system for free. You can also subscribe to "premium" services like Allisonhouse (http://www.allisonhouse.com/) for specialized data such as lightning strikes, model data, etc. They also have a subscription level where you can go back and pull archived radar data even days or weeks after an event has ended. I subscribe to Allisonhouse mainly for the lightning data and the archive features. It also allows you to change the source where the NEXRAD data is coming from, which seems to be a bit more reliable than the "free" source, particularly during very active weather situations.
As far as the geographic storm report maps go, I've been using the Iowa Environmental Mesonet (IEM) located at www.mesonet.agron.iastate.edu/lsr/. They have numerous features on this website, storm report mapping just being one of them. Once you go to the storm report link, you select the NWS Office for which you'd like to plot reports, the date and time range and hit "load" and both a text and graphical representation will display shortly thereafter.
I find the IEM Site to be an extremely valuable tool in severe weather situations, both "live" and in an archived/historical setting. The features on this site are seemingly endless - I'm sure there are things on there I haven't discovered yet either...