GTK 1.x or 2.x?

[Ciprian Popovici <ciprian zuavra net>]

What should I choose between GTK+ 1.x and 2.x for a future
application? Is it possible to make an application compile with both?
If not, should I go with 1.x which is widely deployed, or with 2.x
which is new and shiny but could make some people fail to use my
application? Please bear in mind that (a) I don't need any special
features that 2.x may provide and (b) I'm more or less a newbie, so
the learning curve is an important factor.

-- Ciprian Popovici