As a request
I use:
Raindar (free, shows storm tracks, and info on the storm, echo tops, hail size and probability etc)
Weatherbug elite for general forecast (like 2 bucks or something)
Weather geek pro for models (which I am still learning), I forgot what it cost
Quick weather NWS / Weather bug / weather underground. For fronts and such (free)
Sundroid (paid) not weather related, but its in my folder for sunset sunrises, moon, planetary data and so on) I think this was 2 bucks
Pykl3 radar for level 3 data. The only think I don't like about the program is the lack of storm tracks (unless I am missing something) But it will give you all kinds of radar options, tilts, velocities. Also has more features like SPC charts (mesoscale discussions). This is level 3 data, which is not smooth like say the weather bug app, though smoothing can be turned on, I believe, but lowers resolution and will hide things like gate to gate shear / couplets / debris balls (I think). Warning icons and so on. 10 bucks.
Oh, and a hugely importent piece of software called, TWITTER. Its not a weather app per se, but has been really helpful