One thing to keep in mind about Dabo is that it is **not** geared towards web applications, only desktop apps. Given that everything seems to be moving towards the web, this is a pretty significant limitation with Dabo. Also, as I understand, it is being mainly developed as a side project by two highly skilled but busy people, so progress has been sporadic.
If you want to keep leveraging your hard-earned Foxpro knowledge, you could look into what eTecnologia.net is doing with their VFP NET compiler. Also, bungeelabs.com has an interesting "platform as a service" approach which is quite nice and all-encompassing (language, IDE, testing, source control, deployment and hosting all done over the web, in one site) especially if you develop apps mainly for the web.
However, after all is said and done, .NET might still be your best bet, especially now that the first full version of SilverLight is around the corner. SilverLight could be a "game changer" with its platform-agnostic rich development environment approach, and early adopters will probably be in a good position to take their skills and knowledge all the way to the bank once Silverlight starts to get traction out there. SilverLight apps run on a subset of ".NET-on-diet" completely inside a web browser, and this enables them to run on Windows, Mac and (eventually) Linux, unchanged.
Pertti