In reply to David Staples:
Basically, you can't go too far wrong with any of the walking! Its a truly stunning part of the world.
Assuming you're not going on the summits, many options have been mentioned, here are my faves.
Back of Liathach. Great walk, seem to remember a rough, boggyish bit in the middle, but it was 20+ years ago. Quite a long day, and involves a road walk to make it a circuit - but a rather nice road!
Coire Lair. One of my favourite places in the world, the wonderful stalker's track which climbs surprisingly easily to the corrie rim, beneath the towering flanks of Fuar Tholl, then suddenly opens out into this magnificent huge corrie, is where I'd have my ashes scattered if it wasn't for the fact that I don't want my ashed polluting such a place. For a circuit, head east over towards the Coulin Pass via the lovely spot of Easan Dorcha bothy, a great place for lunch (it basically a little shed by a beautiful stream), then south over the pass itself back to the start.
The little Mountain Nature Trail thing from the shores of Loch Maree is actually quite wonderful, and can be extended onto Meall a Ghiuthais.
Wandering around the headland north of Shieldaig is a very pleasant way to spend an hour or two, finishing up in the Shieldaig Hotel or the little cafe at the south end of the village. The views up the loch are to die for.
God, I love that area. Can I come?