In reply to mattyjones:
The Llech ddu Spur is an absolute must, it's a great route and the horseshoe via Yr Elen makes for one of the best days in Snowdonia so definitely go for it.
There's nothing difficult on Moel Siabod, if you're looking at G2s I'd give it a miss unless you're short on time (it's a fine half-day walk). The East Ridge of Y Garn is my favourite G2 but... I've seen plenty of people back off it so if you're hoping to minimise exposure, work up to it.
Unfortunately Tryfan holds all the best G2s that I can think of: North Buttress, Bastow Buttress and Notch Arete are all brilliant.
Last thought, the G1 on Foel Goch: The Mushroom Garden, a quiet corner of the Ogwen Valley, nice and atmospheric! Stick to the rock as much as possible.