I believe you must have a specific reason for selecting a host that is located in Dallas. Obviously, if you have budget and want more control over the server, you can get a windows server with softlayer directly.
If you do not want any headache in maintaining the server, you can have a look at asphostcentral.com, who specialises in windows and asp.net hosting only. Since you just limit your choice to Dallas data center, there is not much I can see. Hope this helps