@OP,
If you have narrowed down to the logitech G15 and G110 , IMO G110 is a better option if you don't want the LCD screen.
I have G15 and I have never bothered to see what is there on the LCD screen. The USB ports can't be used to plug pen drives and are USB 1.1 means of no use.
With G110 , you will get customized backlighting, USB 2.0 port and 6 extra macro keys.
With G15, you will loose all above features but get a small LCD on keyboard. Now it is upto you what is more important.