Murky said: I'd go for diversity as well for the visual beauty you could create. Two large trees, like oak and maple, and the smaller 3 ones staggered so they bloom at different times. But it's also an excellent point about a disease wiping them all out.
But as crawgarden says, it's your garden and what would you like to see there?
Both. That's why in my own case it's so darn difficult to make decisions. I've been at this for 5 years now
and planted three so far. Here's one of many sketches of my own garden I've made in that time:
The three that are named are currently in. The rest is just hypothetical (including the extra pink one). There are dozens of species I'd like to have...My garden is just too small for my ambitions lol.
And since last week I've been wondering about winter (evergreen) interest too because I never really found it all that important (it's winter so I'm not much out anyways), but we have huge windows at the back, so some green to look at from inside the house would be nice...