Drinky - Never picked up the N64 version of Bangai-O but I heard it was a fair bit different from the DC one?
My order:
-Radiant Silvergun: One of the best shooters ever, IMO (although I've seen so much divided opinion on this game). It was worth the $140 I paid for it, at least

Great music, graphics that still hold up, awesome boss fights (though I agree there are a few too many), cool comboing system, and I actually liked the music. The weapon system totally does it for me, having to use different weapons to get through different areas and aiding your fight agains the bosses is a really nice change of pace from other shooters where you just blow everything away.
-Gradius V: The direct descendent of Life Force, the game that first got me into shooters. Awesome, love the options systems, the graphics are beautiful, music is good, there's a nice 2 player mode. Definitely the best Gradius game ever.
-Ikaruga: A bit too short, and I *STILL* have a bit of trouble with the whole light/dark system, it's kind of hard for me to get used to tuning out the bullets of a single color. Also relies a bit too much on level memorization. I enjoyed it (especially with the Hori pad) though.
-Bangai-O: I can't stand the DC controller, and it won't play on a VGA box. My least favorite part of the game is the Ys syndrome where the enemies ram into you and you don't have any invincibility time between hits, so they keep ramming you and you die in 2 seconds

I've played some of the later levels almost perfectly up until one point, when an enemy did this. But still, the game has an awesome translation and I like the gameplay style.