Most people here use Maverick. Mine is pretty old, so I can't speak specifically as to which of the current models is best, but others on the forum can help with that. A few of us are waiting for the MEATER, as fulfillment from their Kickstarter campaign. You can preorder MEATER (and see details) from the link here, but you might want to wait to order until we've had a chance to test it out and see if it lives up to its promises. Looks like it will probably ship June/July (ignore the March 2016 date they show in their perks). You will want to get something else in meantime anyway.
https://www.indiegogo.com/projects/meater-the-only-wire-free-smart-meat-thermometer#/story