A few out-of-the-ordinary ones that I like:
Good Morning (the one by Flywheel with a yellow-and-blue flower-looking thing as the icon symbol)--Wakes me up in the morning with music, alarm (both pretty normal) but then by reading my calendar entries for the day to me, telling me the weather forecast, and reading any message I typed in.
WakeVoice--Similar to Good Morning, but slightly different. The voice that wakes you makes lame little jokes that change periodically, plus it will read the news. I alternate between the two programs for my alarm on different days.
Astro File Manager--Not that out of the ordinary, but great app!
Galaxy Wire and PhysOrg.com News--Space and science news for geeks.
Mvideo Player--Better video player than the stock one on my EVO 4G, I haven't really compared it to the one on the 3D yet.
FoxyRing--I've never used the program, but I really like the widget that comes with it. Lets you quickly silence your phone for a period up to five hours, but the sound will come back on automatically at the end of that time, even if you forget to intervene.
GasBuddy
EONW (Effects of Nuclear Weapons)--For the morbidly curious creep in all of us.
Pulse or MyTaptu--News feed organizers
RadarNow--Fast, simple non-fancy radar. Essential for those who live in Tornado Alley.
QuintessArt--If you don't care for the art yourself, use it to try to impress cultured women!
Tricorder by Moonblink--Incredibly cool and geeky app, especially if you are a fan of Star Trek TOS. Even if you are too young for Kirk and Spock, this thing uses the sensors in your phone to do some really cool things that actually work!
Wifi Analyzer by Kevin Yuan
I've actually used Sprint Radio a few times as a change from Pandora. I realize I may be the only person on the planet who did this. Occasionally I find Sprint TV has free peeks at channels that are actually worth a darn, and I'll watch 'em if I'm traveling and bored.
I actually enjoy some live wallpapers on a short-term basis till I get tired of 'em for the moment. The ones by Kittehface tend to be good, especially Aquarium Live and Friendly Bugs.