besides PureBasic, I found a very interesting language called EC.
It is derived from (and even compatible with) C and has a platform independant
runtime library (Windows + Unix) featuring almost everything you need.
It compiles (in fact it translates to C) natively and therefore provides almost the
same speed than C.
It is free (I didn't find a licence yet, but you can download the whole package for free)
and the company behind it provides an IDE with integrated designer + compiler + debugger
Find out more at http://www.ecere.com/technologies.html
What do you think, does it worth to take a deeper look?
EDIT: Ahh, I forgot to say it has full OOP support

EDIT2: Found the licence - Free for noncommercial use (http://freshmeat.net/projects/ecere/)...
EDIT3: ...and commercial use, too
