- I program PIC microcontrollers with MPLABC30 , C Language. The screen, tools, menu, compilation, programming are extremely easy and organized ! It saves me time at the industry and the projects work well ;
sure, but what is the need. If you want to go to the '51 learn one thing at a time instead of never knowing if a problem is due to a or b. If you, when you have mastered (somewhat) the assembler want to go to an IDE e.g. keil (eval) go ahead, just learn one thing at a time.

The environment I use to program 8051 with ASM Language has very poor screen, four steps to assembly the code and generate a "bin" file. Another step to generate a "hex" file and another step to upload the "hex" file to the real microcontroller. It works very well and it is doing the job. But, in terms of organization and clearity, compared with the programming I was used to make (C language and PIC) this new method is very worse ; - My objective: A environment clear, with tabs and that generate the "hex" file with only one step... ;
since it is DOS based, why do you not make a .bat file? that will make it "one step"
Also what do you want with a .bin file, the programmer require .hex

As I have explained in a message before, I think better to me read more about the options of IDE before a new topic (Neil suggested me search at the LINK menu, I am doing that! )
again, as said before one thing at a time. You have stated "I am new to '51 assembler"

Erik