Advice requested: GUI project beginning

[Russell E. Owen]

I am starting work on a telescope remote control user interface. It's a 
big program with lots of windows and controls and display graphics 
supporting the telescope and numerous instruments.

Python is a leading contender because I'd like a system that offers:
- rapid development/change/test
- robust
- safe (automatic garbage collection and bounds checking)
- runs under both unix and MacOS, if possible (windows wouldn't hurt, 
either)
- will probably be around in 10 years

My development platform is Mac. I'd like to stick to that, but fear it's 
not reasonable with Python because:
- No threads on the Mac. (yet)
- Tkinter is flaky on the Mac. For instance it doesn't run in the IDL 
and it doesn't fully quit.

Any comments? If I do switch, is Python development or support notably 
superior under unix or windows -- aside from OS preferences? (Please no 
OS flame wars.)

What Python windowing environment do you recommend for a new project? 
wxPython? Tkinter? Java (via JPython)? (Is there anything else?). I'd 
prefer something that is easy to use and scalable.

-- Russell

P.S. I am also considering Smalltalk (superb language, but ugly GUI and 
hard to sell to folks used to C/tcl/perl) and Java (reasonable Mac 
support and long-term prospects, but not very malleable). Are there any 
other languages I should consider?