Agassi, well, he was always in the shadow of Sampras, so it is difficult to rank him. I am curious, mountaindewslave, what would your top 20 be?
TOP 20 would be difficult to think of at this moment given I have limited time BUT I think your list could have been much worse I just do not agree that (for example) Pancho deserves the #5 (the same goes with EVEN Tilden) and it's not to say they were not immensely talented, it is to say that there is no real way to gauge them given the fact that the sport was just not competitive like it is today! Esspecially in Pancho's era, the incentive for players was SO MUCH LESS.
Nadal should not be behind Llendl that's for sure! Agassi may have been overshadowed but that return is hard not to notice and Agassi would have accomplished a lot more had he not had so many internal issues.
My top 20 I'm not sure at this moment, I would have to think about but top 10 would come off as rather cliche' with something like, #1 Federer (Never in doubt, look at that technique!) #2 Laver (At least had some action in the OPEN era), #3 Borg (One of the most raw talent and raw athletic players ever seen,do not agree that it is so much that he burned out as much as that he lost interest, imagine the possibilities if Borg had not retired so young!) #4 Conners (simply because of the miraculous nature of his career, incredibly feat winning so much and for so long at such old ages! not to mention I believe? he has the record number of overall TITLES) #5 Sampras (Amazing on grass and that serve! BUT I think the conditions of the 90's really helped him and the clay issue prevents Sampras from being a few ranks higher), #6, Rafael Nadal (best player on clay of all time and possibly the greatest adapter the game has ever seen... arguably a better 'fighter' than Borg, #7 Agassi (best returner of all time and could of done so much more if not for internal struggles/ brilliant handling of the second half of his career), #8 Mcenroe (Beautiful on the grass, one of the best tennis touches ever), #9, Llendl (8 US OPEN finals in a row! Very worthy given his resume of titles and GS finals, but quite depressing when one looks at his record of losses at the GS level and what could have been), #10 Budge (just for being so consistant and for being the first to accomplish such sick runs at Grand Slams simultaneously, 6 in a row starting in '37)
would be very hard to manage a top 20 let alone 55