TorqueDev is very very nice, it has realtime error checking, syntax highlighting, and if you select the visual basic theme, it has a little menu pop up with local variables, known functions and commands, and other stuff, depending on the letter
Example - I type "p" it pulls up in the menu "Package" "Parent" "%poo" "$Poo::Derp" and a lot more stuff that begins with P. Very, very useful.