
Dropzone is a good choice, but is it old enough?
There's an MSX defender clone called "Desolator" which is incredibly good, and it has some crazy stuff like suicide warps, enemies that steal power-ups icons (And actually become STRONGER

Hmm.. maybe Uridium on the C64?

We could also go for the Atari 2600 version of Defender, though this one sucks (Though I played it a lot back when I was like 4 years old and I loved it

ANd yeah, please NO Space Bomber. We already played that in the older shmeet.
Doesn't Gunbird 2 and Dragon Blaze have lots of experienced players?
I'd say, let's go for Sengoku Ace, Strikers 1945 Plus, Sol Divide (eh?:D), Sengoku Blade and..... hmm.. Strikers 1945 I? Or.. erm... Dragon Blaze, heh?

Does it always have to be 5 choices?