If you can easily manage your luggage the Light Rail is a good choice. It's $2.75 from the Airport to the end, Westlake Center, which is in the center of downtown. You need to walk 7-10 minutes to reach the Airport Station and another walk to whereever your hotel is located.
Stila Towncar and Yellowcab are both located in the aiport. Stila's walk up sign says $45 to downtown. A cab is about the same. Depending on traffic and time of day, it's about 25 minutes.
Or look at various options offered by www.shuttleexpress.com
. They have a scheduled 'Downtown Airporter" service that drops off at several hotels.