Edit Nov 2011 - a retraction
Most of what I say below is still true however I have now got serious reservations about recommending REALbasic for anyone trying to release commercial-quality applications. To save me remembering to edit this post later, see if RealSoftware have managed to release a robust version of their IDE using the Cocoa version of their frameworks. If not, be very cautious.
It's with a heavy heart that I write this because I still really like the language and think the framework and IDE are well-done. The problem is apparently one of under-capitalization and possibly a software development culture inside the company that consistently fails to deal with a bug regression problem. Many bugs are fixed each release but there appears to be a huge tax on the developers in the number of introduced bugs. They have a very small team for the complexity of the product, especially considering the newly released Web Edition which is effectively an entirely new platform.
It's still theoretically a great product but take advantage of the trial period, test it thoroughly on each of the platforms you plan to target and decide if you can live with any bugs you find because they may be there for a while.
REALbasic.
The language is a powerful, modern OO language that won't be hard for you to adapt to from your vaguely remembered Pascal or current JavaScript. It has most of the power of C++ without the dangerous bits that make debugging a nightmare. You will also find the IDE simpler and easier to deal with than say Visual Studio.
The IDE makes it very easy to throw together a GUI and have it just work on multiple platforms. The Pro version has one of the best cross-platform debuggers I've used and it is easy to just work (say) on a Mac and develop for Windows and Linux, compiling and testing with one click.
There is also a thriving community including many people at your level of expertise so you won't be mocked for being a newbie.
I am a professional software developer with over 25 years experience and currently mainly working in REALbasic, C++, C#, Objective-C and a bit of Ruby. For apps such as you mention, REALbasic is my tool of choice.
edit: I can't believe someone downvoted this but didn't have the guts to add a comment explaining why. I'd heard about prejudice against REALbasic but this is the first time I've encountered it. In what way was my answer inappropriate for this question?
Just to add to my cred, I've implemented cross-platform frameworks used by systems deployed to tens of thousands of end users - I have the C++ cross-platform experience to applaud someone else doing a good job and the REALbasic frameworks are very nice.