ok here is my opinion. i used to drink blends quite frequently in college and even up until i went to Scotland. then i tried single malts and i can definitely tell a difference. single malts have more flavor and are much smoother. blends tend to be harsh. i can now tell the difference between a blend and a single malt. as i was told by the tour leader at Glengoyne - blends are ok to have. they are really meant for mixing. but single malts are meant to be enjoyed and savored.
soooo, if you are looking to just mix a drink and not enjoy the flavor of the liquor itself - go for blends. if you want to just sit, sip and savor, go for the single malts.