In reply to Fat Bumbly2:
> St Kilda from Sgurr nan Gillean.
> Cheviot from Lochnagar.
Similarly a pal and I could see St Kilda - both main island groups quite distinctly - from the summit of Beinn Edra on the Trotternish ridge on 19 October 1999, a very clear day. Re Lochnagar views, the Cheviot could be seen from the summit on 18 April 1983 (suspect it's in view relatively often).
And rather frustratingly in retrospect, I've been up Merrick on an exceptionally clear day (5 September 1992), but although I can remember seeing Ireland and various Highland peaks (including Cruachan, at 93 miles according to JdF's panoramas), I can't remember looking for Wales. There wasn't any early snow, however, so chances are I'd have struggled to see Snowdon even had I looked.