personally i use the RIM JDE most of the time, it has its limits but the integration with simulator and signing tool is helpful.
i think you can include the simulator into eclipse
(read this thread), i tried it for some time, didn't manage to have it run properly so decided to stay with the JDE.
to begin with programming i would suggest to build a screen, a menu and maybe a second screen. put in some functionality and create a socketconnection to some server-component and transfer the data.
if you are familiar with java a sql-connector (running on a PC) is a nice thing to have, if you discover the possibilities you get ideas quickly