There's also Castle Shikigami 2 on PS2, if you can find it. I don't think they made very many of them for the US market.
There have been plenty of shmups for PS2 and especially Dreamcast in Japan in the last few years...ya got yer Border Down, Chaos Field, Psyvariar 2, Zero Gunner 2, XII Stag, Trizeal, DoDonPachi Black Label...but I do wish any of these would be released outside of Japan.
I'm a big fan of the shmup genre and have a pretty nice collection of them across all platforms. Years ago, when I was at the height of my shmup-mania, I could blaze through G.Darius on the very hardest difficulty setting, beat Sokyugurentai without continuing, and had my levels maxed out in Radiant Silvergun so that I could beat it on a whim -- those were the days! =) Sadly, my skills have deteriorated somewhat since then, but I would like to build them back up again someday.
If you wanna check out an older shmup that's really impressive, find a rom of a Famicom game called Recca -- it was made for a Summer Festival contest in Japan and it's extremely rare, so don't bother looking for the Famicom cart unless you want to drop several hundred bucks -- but it's insane, not only for the gameplay, but for the fact that that gameplay is coming out of a Famicom. It plays like a modern shooter with tons of fast enemies and loads of buckshot to avoid.
mmmm...shmups.