Here is the hotkey layout I've been using for several months now:
I play Protoss, but the layout includes keys for Zerg and Terran units also (though these are not as well tested).
12345`TYGB. I use 1-5 for armies, letters for production buildings, and
`for an observer.
Alt-FDREto set them. I use these for bases.
WERfor most units. Non-spell building abilities (such as Upgrade to Hive or Load SCVs) and the ghost's remaining spells are on
ERused for casters or other special units.
This layout is designed to be used with a Control key where most keyboards have Caps Lock (as shown in the diagram above), though it will still work on other keyboards.
`in the QWERTY layout) cannot be used. Instead, control group 6 is moved to the
Documents/StarCraft II/Accounts/account number/Hotkeys, and they will appear in your list of hotkey configurations in-game.