combo box terminology

[Ben]

i'm working on the standard terminology section of the style guide. I've 
been borrowing heavily from the gnome style guide, but writing in my own 
words, as we are releasing into the public domain. However, the combo 
box it a bit tricky. The gnome guide says to use drop-down combination 
box rather than combo box- i agree, but what do you all think?

also, should it be:

Choose <userinput>Ubuntu</userinput> from the <guilabel>Operating 
System</guilabel> choices.

or

Choose <userinput>Ubuntu</userinput> from the <guilabel>Operating 
System</guilabel> [combo box/drop-down combination box].

I prefer the first.