Kolibri it's not very good IMO. I always heard good things about it and when I finally managed to play it on a friend's 32X I was like "Heh?".
Also it was made by the guys who butchered Castlevania on our Amiga, so fuck them.
Gradius V wasn't developed by Konami. It was designed by Treasure, with G-Rev doing most (if not all) background graphics. Konami was obviously the publisher. Unlike most shmups of its era and previous Treasure shooters, I like the fact Gradius V doesn't have any complex scoring system that goes beyond "Kill most enemies"... and the level design and boss design is just out of this world, that game is freaking awesome.
But IMO it has the same problem of Radiant Silvergun. Sometimes sections of it are a chore to play it and its TOO FUCKING LONG. But I still think it's the best Treasure Shoot'em up by far (And I am acting like Silpheed: Lost Planet never happened) and it's surely on my top 10 shmups of all time, it's really an amazingly good game.
But I still think Gradius Gaiden is a better game that aged better. IMO Gradius Gaiden is the best Gradius game, the best Konami shoot'em up, but it's not the best PS1 shooter.
That goes for Zanac Neo, which I believe no one mentioned on this thread.
If you haven't played Zanac Neo, go do it now... It's my favourite shmup of all time, it's amazingly fun to play, it has a killer soundtrack, it has some real cool boss design, it has that hectic fun gameplay so characteristic from Compile, it has a shitload of different weapons for you to toy with, an interesting score system you can completely ignore if you want it, a fair amount of secrets to figure out....
It was really the perfect swan song for Compile. I was really sad when they went bust (I remember the day and where I was when I read those news), but I was glad they went with an amazingly good (best ever?) shoot'em up that was really strong to their roots, instead of another Puyo Puyo* game or some random average action RPG.
(* just to be clear, I *love* Puyo Puyo
)