I'm really surprised upon reading this thread that noone has mentioned Teacher's Highland Cream... I was put onto it by a high rating in Jim Murray's Whisky Bible. I figured I'd try it out and see what the hype was about, and low and behold... I loved it! "Cream" is right... its like drinking whipping cream.
I don't see how Ballantine's (except for one of the higher end, maybe 12yo blend, that I tried once and really liked) or J&B could stand up to it.
Funny thing is, only a couple of months after I was onto Teacher's, and part way into my second 26er, I was out one evening at a get-together, with a friend who is in my whisky tasting group, and I brought a bottle of Teacher's. We were talking about our upcoming meet and which single malts we hoped we'd be tasting and he pointed over at the table where I'd set my bottle of Teacher's. He said: "Have you tried that stuff? I just bought a bottle of it this week and it's excellent!" He was really excited...
Anyhow, give it a try, if you haven't already.