You said WWE so, I will take it as WWE. Shawn Michaels is certainly not the best WWE wrestler that there has been. Maybe in the history of the company but, the WWE should only count to 2002.
JBL. This man made his way from a tag team wrestler to a main eventer with ease. He was pushed in a space of two months and had no problem carrying a show. He carried the SmackDown main event scene for roughly 10 months and carried a feud with Taker. He also created The Cabinet, a very weak stable on paper and turned them into a force to be reckoned with in professional wrestling.
After losing the title, he still stayed how he was. Cutting bad ass promos and making every storyline he was involved in interesting. His work with Shawn Michaels towards the end of his career was one of the best angles Raw has seen in a long time. He is, in my opinion, well deserving and though he is usually underrated you cannot deny that heat followed this man wherever he went.
Most notable feuds;
Eddie Guerrero. The starting point in his heel turn, very entertaining. If any of you guys have never seen their match at Judgement Day 2005 you have to watch this. Not in a long time have I seen such emotion put into a wrestling match. One of the few main events that finished in a DQ where I didn't mind because of the quality of the match.
[video=youtube;t7gmxaE8fgo]http://www.youtube.com/watch?v=t7gmxaE8fgo[/video]
[video=youtube;8XDOYm7YTx4]http://www.youtube.com/watch?v=8XDOYm7YTx4&feature=mfu_in_order&list=UL[/video]
[video=youtube;x9cztlIwQSw]http://www.youtube.com/watch?v=x9cztlIwQSw&feature=mfu_in_order&list=UL[/video]
The Undertaker. This feuded cemented JBL as a main eventer and a capable world champion. JBL's character stayed so resourceful throughout that he was one of the few men to face the Undertaker and to not be a huge underdog. The Last Ride match at No Mercy from this feud was great to watch too. JBL kept the belt during the feud, this put him over as one of the WWE's finest. At this stage, I felt that he had surpassed Triple H and became the strongiest heel in the company.
[video=youtube;e-_yCxVFhKE]http://www.youtube.com/watch?v=e-_yCxVFhKE[/video]
[video=youtube;tRTOJaBA4lw]http://www.youtube.com/watch?v=tRTOJaBA4lw[/video]
Shawn Michaels. One of the best angles that Raw has seen in years. This feud showed off JBL's character off to a new generation of fans, needless to say that the little kids in the audience couldn't bare to see HBK being bullied by JBL. Great twists throughout and a few good matches came as a result of the feud. Not to mention that we seen some of JBL at his finest during promos.
[video=youtube;oyoL-oiyXC4]http://www.youtube.com/watch?v=oyoL-oiyXC4[/video]
In case you didn't know I'm a huge JBL mark. Chris Jericho was an honorable mention.