Holiday Inn Express (984 U.S. Hwy. 287 Bypass W., 972/938-3300, $93 d) is a nice, new hotel that handles the basics effectively with above-average service and amenities, including free buffet breakfast, complimentary Wi-Fi, and a free daily cocktail hour.
Another decent option is Americas Best Value Inn (795 S. I-35E, 972/937-4982, www.bestvalueinn.com [1], $99 d), which includes free continental breakfast and an outdoor pool just a half mile from downtown.
Slightly more expensive and upscale is the Hampton Inn & Suites (2010 Civic Center Dr., 972/923-0666, www.hilton.com [2], $114 d), offering a free hot breakfast and studio suites.
Links:
[1] http://www.bestvalueinn.com
[2] http://www.hilton.com