Getting the right amount of whisky influence on the ale is definitely the key thing for me. I've always liked the Innis & Gunn range, feeling that they've got the balance spot on. On the other hand, I had a bottle of 1488 a while back and found that it had far too much whisky character, making it a little unpleasant and even difficult to drink. (Others will love it, of course, but to me less is definitely more in this case.)
Brewdog's Paradox ale is also very good, if a bit pricey. I've not tried any of the Ola Dubh range, but next time I see a bottle I'll pick one up.
"When you go home, tell them of us and say,
For your tomorrows these gave their today."