Just back from the Outer Hebrides.
The wildlife there is outstanding and some highlights for me included:
Short eared owl (loads)
Hen Harrier (male and female flying regularly within 10 metres of my digs)
Golden Eagle (several)
White tailed eagle (several)
Ringed Plover
Puffin
Red throated, Black throated and Great Northern divers (all within the space of an hour)
Cuckoo (juvenile - very close)
Red deer - loads
Gannet
Manx Shearwater
Guillemot
At least two species of dolphin (don't ask me what species!)
Seals aplenty
The great thing in the OH is that you don't really need to try to hard to see this stuff - it's all over the place.