Already have Shining: the holy arc and looking into getting Resident Evil.

Any other gems I really need to keep an eye out for? Importing isn't impossible either, so don't be afraid to metion Japan-only releases.

Edit: Primarily on the look-out for Salamander-styled SHMUPS, and I still need some convincing on Princess Crown, namly the random incounters with in a side-scroller.

Panzer Dragoon?
Nights?
BURNING RANGERS?

Legend of Oasis
Maybe Virtua Fighter, but definitely Virtua Cop.

I love SHMUPs, so off the top of my head:

Darius Gaiden

Batsugun

Battle Garegga

Layer Section

Soukyugurentai

Salamander Deluxe Pack Plus

Thunder Force V

Panzer Dragoon Saga... expensive but it's worth the money..

Depends what you like...

Action games -
3 dirty dwarfs, Panzer Dragon Zwei, Guarden Heroes

Fighters-
Fightes Megamix, Street Fgihter Alpha 3 (needs Ram Cart), Marvel VS Street Fighter (Ram Cart), Mortla Kombat Trilogy

Platformers-
Astal (amazing game), Nights, Bug Too (its alright not amazing), Sonic Jam

Shooters-
Raident Silvergun, Batsugun, Layer Section

Adventure -
Castlevania SOTN, Legend of Oasis

FPS-
Powerslave, Duke Nukem 3D (best port of all 3 systems), Quake (little ugly but playable)

RPG-
Grandia, Panzer Dragon RPG

Racing-
Sega Rally, Wipeout, Daytona USA

Get Lunars. Only available in Japanese but you don't mind that.

Don't get the Lunars. The PS1's version is better from what I know.

Get Albert Odyssey: Legend of Eldean.

Then you don't know enough. The Saturn and PS1 version (complete ones) are indetically the same, just that Saturn ones have better sound quality (and they are cheaper). Theres also Magical School Lunar, which is a great game, except for the encounter rate.

The FMV is better on the PS1 from what I hear.
And more bromids too.