2010 was quite a banner year for WWE to say the least. There's quite a few moments for me to pick from. I'm gonna narrow it down to 5.
Of course, there's the Return of the Hitman, after a self imposed absence from the company that he felt killed his brother, and he said he would never ever return in anyway to do any promotions, everyone was

. Dennis Miller started a bit of a rally back around the time he did the Slammys to get Hart back in. Then to add even more power to the punch, we see Hart and HBK make amends. It was so much more sweeter than expected.
HBK's redux of his match with The Deadman at WM26, and subsequent retirement. Needless to say, 09 and '10 belonged to HBK for personal achievement best. His WM25 match was so superior, no one thought it could be matched. But lo and behold, he was a mad man on a mission to get his re-match with the undefeated 'Taker, even sabotaging a PPV match of 'Taker's and getting him to accept the challenge, to where it was Streak v Career. Sadly, we ended up losing our Mr. Wrestlemania. It proved to be a sad Monday Night Raw that night as HBK proclaimed "Folks, HBK has left the building." Then he left his trademark DX glowsticks as a tribute to the fans.
Old School Raw. Of course this was AMAZING to see. I really felt like I was back in the good old days, and everything was right with the world again. Loved seeing Mean Gene, the Iron Sheik, and LOVED seeing Mae Young call out Lay-Cool. The saying "What was once old is new again" proved true that night. I was so glad to see that.
Kane winning MITB, and subsequently cashing in that same night. I was glad to see Kane get a great shot. He won MITB, and then that night, it looked like he was doing a great deed by helping Mysterio against Swagger. Then he turns around and cashes it in!!!

Way to go Big Red Machine. This turned out to be some of the best mic work by Kane. I'm a little sad that it took so long for the powers that be to let it sit this long to let him have this kind of push. Even thought it wasn't as long as I'd liked, it was good while it lasted.
NEXUS. The name says it all. Headed by the Brutal Brit, winner of Season One of NXT. No one knew for sure what lie in store for the young man from Manchester, a bareknuckle brawler. Then the night of the Viewer's Choice RAW, we saw Cena v CM Punk, and during the match, out comes Barrett, and you saw the other cast offs from NXT, as they stormed the ring and left everything they touched in a pile of rubble.

It was the perfect storm. From that point forward, they were quite the force to be reckoned with. Even to Summerslam, and on to the battle that forced Cena to join them, then to eventually forcing Cena out of WWE (albeit temporarily.) This was by far a year that Nexus affected ALL of WWE.