For the single malts I like the smoky, peaty, iodine flavours. Laphroaig, Lagavulin.
For sheer robustness and layers of flavour it has to be Talisker.
For the softer, more subtle caramel / butterscotch / honey / heather notes, I like Auchentoshan, Oban, Glenkinchie.
I was very pleasantly surprised by Penderyn, the Welsh single malt. Very tasty.
For the blended ones, Chivas Regal and Stewarts Cream Of The Barley.
My late father used to say that there's no such thing as bad Scotch, just good Scotch and better Scotch. I almost agree with him, except for Johnnie Walker Red Label, Vat 69, and Cutty Sark. Yeucch!