I am absolutely disappointed at the lack of Indie Game recommendations.
I guess I'll be the first.
I would say grab the entire Radiangames series, but they just jacked up the price to 400MSP each. If you have tons of money to burn, I highly recommend all seven games.
Sequence is what would happen if DDR and Puzzle Quest had a baby. A really spasmodic baby. Great voice acting, funny humor. I found it to be a tad easy though, even on the hardest difficulty, but that's just me. 240MSP
Echoes+ is Asteroids on steroids, with a Geometry Wars style twin stick flair. 80MSP, totally insane for what you get. Speaking of insane twin stick shooters, Score Rush is a twin stick shooter with bullet hell elements. Tiny hitbox, rain of bullets, you know the drill. It's also co-opable up to 4 players locally. 80MSP, can not recommend this game enough.
Want a more traditional bullet hell? Vorpal will cover that. 80MSP
Head Shot 2 is a sniper game. Find a target within a crowd, and pop a cap in his skull. 80MSP
I MAED A GAM3 W1TH Z0MB1ES!!!1 is a zombie twin stick shooter. Also has the greatest song in the world. 80MSP
Do you like Warning Forever? You will absolutely love Infinity Danger. 80MSP for boss rush heaven.
Prismatic Solid is an amazing shmup. You also control these little satellite things that can shield you from all sorts of bullets. (You'll need them.) 80MSP
Back to bullet hells, REVOLVER360 is a horizontal shmup that lets you rotate the world. That wide spray of bullets coming at you? It's now a line. 240MSP
While we're on horizontal shmups, Leave Home has fantastic presentation, and the game never plays the same way twice. You have five minutes to get the best score, and what levels you get depend on your performance, so no game is too easy or hard. 80MSP
If you're up for a battle of minds (and a little luck), Tacticolor is what Risk could be like if it was a real time strategy game instead of a traditional board game. 80MSP
And for those times when you need a break from all the genocide and murder, Avatar Drop is whimsical fun for the whole family. Drop your poor helpless avatar ragdoll through rings for points and stuff. 80MSP
Now, let's get into disc games...
If you do fancy bullet hells, look around for WarTech: Senko no Ronde. It's a versus bullet hellish game. Spray bullets, dodge their spray of bullets, don't die, etc. It's pretty unique. I found a used copy at Gamestop for $3 ages ago, can't imagine it being no higher than $10 on the internet.
If you like racers, Import Tuner Challenge might interest you. If you liked the Tokyo Xtreme Racer series, stop reading this paragraph and go find it. This game is Shutokou Battle X, just with a stupid localized name.
I also happen to like the Dynasty Warriors series. Dynasty Warriors 7 is the definitive DW game. If you're a fan of the series, grab it.
If you can find it, Qubed is Lumines Live (with most of the DLC), Rez HD, and E4 all on one CD. Shouldn't set you back no more than $30, and that's kinda high seeing how old this disc release is.
Deathsmiles is another nice bullet hell shmup.
And other recommendations in no particular order:
Sonic Unleashed (I don't care what anyone says I think this game is pretty good)
Need for Speed: Shift and Hot Pursuit
Magna Carta 2
Tales of Vesperia
Forza Motorsport 3