Boot media optimum type/size - is there any difference?

[Tim0]

Hi, I'm just a newbie here trying to get Openelec setup for an ION HTPC (ASUS AT3IONT-I DELUXE + 3TB HDD for storage + 60GB SSD for Win7). What I'm wondering is this: is there any benefit to having a larger/faster Openelec boot media (USB stick, SD card, etc), or will any old one work just as well.

Also, does Openelec support 3TB hard drives?

Any help is much appreciated!