If you are only going to stay one night, I recommend The Arlington (
http://www.arlingtonhotel.com ). It is in old town (downtown) and across the street from Hot Springs National Park, and within walking distance to everything else downtown. And the rates are reasonable, wide variety of rooms from nice low end ones up to high end suites.
There are several beautiful lakes outside of town and tons of hotel/motels around them. But I think that downtown is better this time of the year. The ride is beautiful all around Hot Springs, tons of lakes, hills, trees and winding roads.
Be sure to take a quick ride up the mountain to see the lookout tower (
http://www.arkansas.com/attractions/attr_detail.aspx?id=17490&r=Ouachitas&city=Hot%20Springs ). The ride is very nice and it is only a few minutes from the hotel.