Great Fighters Who Still Need a Defining Fight

All in the title really. I'm talking about fighters in the end of their prime or in their older years who still need that one fight that will define them. So please don't post something about Chad Dawson or someone like that. I have a few suggestions: Vitali Klitschko: I'm not even sure if there is a defining fight out there for him, except perhaps Haye, unless he were to change his mind and fight Wladimir. Whether you like him or not, Vitali would have probably been a top heavyweight in any era, if not a champion. His sheer size, power, chin and solid fundamentals would see to that. Where are the great wins on his resume though? At the moment he is defined by an unfortunate loss to Lennox Lewis. I don't know about you, but a near victory against an aging and out of shape great isn't a definer for me. Some might nominate his victory against Peter considering how long he'd been out of boxing, but being completely honest, I think most of us can agree that Peter has never been a great fighter. Wladimir could easily be here in his place, but the reason I chose Vitali here is because I feel Vitali doesn't really have the blemishes on his resume that restrict me from considering Wladimir a 'great' fighter. Juan Manuel Marquez: Perhaps a controversial choice considering his victories over Barrera and Diaz. Especially considering how close his fights with Pacquiao have been (arguably victories). I'm looking for something more here though, as Barrera was past his prime, Diaz is perhaps a little limited to be a definer and a draw against Pacquiao just isn't good enough for a fighter this talented. Marquez is one of the all-time great counter punchers as far as I'm concerned and perhaps the best example in boxing today of the term 'the sweet science'. Those victories and that draw could be good enough to be definers for most other fighters, but Marquez is something else. It needs to be a victory and it probably needs to be over Pacquiao. Floyd Mayweather Jr: Ok, so he is retired and perhaps he shouldn't count here, but it still doesn't really seem like he is done. 39 and 0, titles at five divisions, victories over De La Hoya, Castillo and Hatton; you might ask 'what more can this guy do?' He needs that risk fight, he needs that one fight that you're not sure if he is going to win or not in and he needs to perform spectacularly in it. His resume seems too safe at the minute, despite the excellent names listed. Sure, Mayweather was the naturally smaller man against De La Hoya, but I think it was clear to the hardcore fans that Mayweather was going to win. De La Hoya is traditionally a guy who doesn't quite perform on the biggest occasions, more best of the rest than best of the best. As for Hatton, some got caught up in the possibility of him manhandling Mayweather (including myself to an extent, as I gave Hatton a chance), but in reality Hatton never had the skill set to win and his style was tailor-made for Mayweather. Pacquiao or Mosley might be the only contenders left for Mayweather to finally define himself against in my opinion.