This is a known and personally experienced issue (Tech Preview and Beta Builds as well) with Datasheet View not working in SharePoint if you have Office 2010×64 clients installed on your workstation.
Again this is one of the FAQ on the MSDN Forums and today I saw the solution posted on the thread, so comes this post for my reference and in case you experience this, then you know what is the solution to the issue.
Office 2010 Technical Preview was officially released this week at WPC and tweeps (people on twitter) have been sharing their news, experience, new features, etc already. You can keep up with the latest buzz using BingTweets.
I have compiled a small list to get started with Office 2010! I would recommend adding all Microsoft related blogs to your RSS reader and if you are on twitter, follow