For my mobile setup, I ordered the Maxrad BMAXSCAN1000S from
www.randl.com for about $30. Seems to work decently well on all bands for me. It's fairly short and stealthy on an SUV. You'll need an NMO type mount for this one, either a thru hole mount or mag mount (if you're not into drilling holes in your vehicle).
For a base setup, I'd recommend a wideband discone type as these tend to have good reception across the spectrum.