Serenity Now! is the clarion call of that inimitable Seinfeld character who looks for peace and quiet in all the wrong places. Too bad he didn’t know about the luxury spas below. Each one offers no end of peace and calm. You’re likely to pay dearly for the experience, but it’s one you won’t soon forget. Amangani (Jackson, Wyoming) It’s all peace all the time at this all-suites resort, where western hospitality complements Eastern simplicity — high ceilings, platform beds, and large soaking tubs. Just gazing at the mountain and valleys is therapeutic enough. The spa and fitness programs are icing on the cake. (photo, right) St. Regis Monarch Beach Resort & Spa (Dana Point, California) With luxuriant, fully wired rooms and round-the-clock services, this 172-acre resort mixes modern comforts with more traditional flourishes. Pacific Ocean views complement the world-class spa and championship golf course. Can’t live without your room’s plush robe or Bose wave CD player? Order them from the Monarch’s store. Arizona Biltmore Resort & Spa (Phoenix) Entering the 1929 landmark hotel is like stepping back to a gentler, more refined era. One way to escape from modern-day pressures is to rent one of the private cabanas near the Paradise Pool—they’re equipped with mineral water, shower, and phone. (photo, right) Greenbrier (White Sulphur Springs, West Virginia) The grande dame of spa resorts has a genteel air — think afternoon tea and dressing for dinner. The old-world grandeur …