Tony, just to elaborate a bit on the sear/reverse sear...
Brian explained it perfectly. Where the "reverse sear" comes in is when we depart from the "traditional" method of cooking. If you read recipes, or watch cooking shows, the conventional wisdom is to sear the meat, with high heat, before roasting. The problem with this method, from a smoking perspective, is that it begins to cook the meats outside prematurely, and you end up with an over-done surface. If you brown the outside prior to cooking, that surface meat is much hotter, and cooks at a faster rate than the middle, so if you're shooting for, say, a "medium-rare" finish (prime rib, sirloin tip roast), you end up with a medium-rare center, and a medium-well 1/2" exterior. By smoking low and slow to the desired internal temp, and then searing at the end for 5-8 minutes, you maintain the desired internal temp all the way to the edge! If you look at my prime rib pics, under "Beef," you'll see closeups of this.
If I want an internal temp on anything other than medium-well, I use the "reverse sear" method; works fantastic!
