Probably Grahame Smith. His main contemporary competition for openers spots will be Cook (who he trumps) & Hayden- fans may be split evenly, very close. That is assuming Hobbs & Hutton can be left out as too hard to judge now.
Greenddge , Gavaskar will be his other partner or contenders. Greenidges stats & away form don't really stack up (higher % of match winning knocks due to him, or the strength of his bowlers turning runs into victories?).
Smith/Hayden (so similar that most will pick one & leave the other), Gavaskar is probably the best combo in the last 50 years.
And no, Sehwag is not a contender- not good enough away. Put him with Jayawardene.
Steyn is magnificent to watch and a champion bowler- but he's probably with Andy Roberts, Allan Donald, Courtney Walsh, Michael Holding etc as wonderful bowlers but how do you tip out McGrath, Lillee, Marshall, Ambrose, Wasim?
Let's try like for like again and assume we pick 3 quicks. McGrath/Ambrose had a similar enough skill set, height & style- admittedly some differences but if I'm putting together a perfect attack, they fill a similar role. 1 spot there.
Lillee/Akram- different arms, different careers but both quite complete & versatile. Some will regard Lillee as then ultimate fast bowler. Some will say he didn't do enough in Asia. Some will love the swing & style of Akram & want a left armer. Some will never pick him because of fixing & say Sobers bowled left. Again, either one will regular earn a spot in ATG teams. 1 spot there certainly, whoever you choose.
That leaves Steyn/Marshall as shorter, rapid swing bowlers. Tremendously close in stats, given the era Steyn bowled in. But good as he was Steyn was not as lethal in the backyards of the best batting units of his era, whereas Marshall was. Marshall will edge him out of most XI's I think.
Kohli, Root, AB, Smith- perhaps but each one needs a few epic series to really be in the conversation. Those ATG batting lineups are insanely strong.