My favorites are (in order):
My least favorites (In order):
Bertram (nn. Bram)
You have a great list so it's tough to narrow down, but here it goes.
Top 5, in no order..
2. Bertram (nn. Bram) - what about Bennett instead?
All of these are great classics that I feel wear well on a little boy and age nicely.
My least favorites:
Bertram- Bram (instead of Bertram, I'd rather see Abram or Abraham)
Hamish- I feel like teasing will occur
Jago- It's interesting but it *might* be hard to carry for someone like a doctor or lawyer.
Gerard- This feels very stuffy to me, not my favorite.
Graeme- There might be pronunciation issues.
Dexter, Eliot, Ethan, Henry, Martin are my top 5 from your list.
Bertram, Gerard, Jago, Russell, Tobias are my bottom 5 (although I do like the nn Bram I just don't like Bertram).