They are hard to find, but my best friend had one for 19 years, and she was a super sweet, loving, gentle, BUT good watchdog. The nice thing about their hair, is that it is soft and curly - unlike most other terriers. Another great terrier like the Kerry Blue in personality, is the Soft Coated Wheaton - they are smaller, and have off white to light tan soft fur - great dogs. With BOTH, you do still have to have them groomed unless you learn to do it yourself AND have ALL the proper tools - including a grooming table.
I am a huge fan of the large terrier groups AND of Doberman Pincher's. Another of my favorites is the Bull Terrier - not the pit bulls, the English Bull Terrier - awesome dogs.