Here's the way I see it:
This kind of topic will always vary depending on the point in time we are referring to, I'm not gonna take in account overall achievements, I'm just gonna go with the "peak" level factor. I know it's overdone and a rather stupid term but I think these standings are way different to the ones done based on rankings, slam performance and how used we are to the players being at the top.
So I'm gonna go with this:
1.Djokovic - this guy has a Balcanic temperament, thus why he has underachieved at slams, but if he strictly talk about groundstrokes here, he is at the top for me. At his best, he is simply unplayable, he can defend as well as attack. Both his forehand and backhand are the most vicious groundstrokes on the tour right now. The shame is that we can't enjoy them right now, this year due to Novak's continuous problems. Once, he had the best backhand on the tour by far but things have changed in that regard lately. That open stance forehand is pretty legendary.
2.Federer: what's there to say here?...sure, the backhand can be considered a liability, but it's done more good than bad for Federer in his career IMO, and Roger has one of the better one handers on the tour and it has been that way for most of his career.
3.Soderling: Well, in the last year or so we have been proved why. He is not the most consistent of them all, but he's getting there.
http://www.youtube.com/watch?v=k6AEGMspr18
From the second set onwards we have a clinic.
4. Nadal. Based on current form, I'd probably put him in front of Soderling here, but I don't want to be biased based on recent results. He has gotten very good, he is so solid with his backhand, it's pretty incredible. The forehand is as good as ever and I'm only putting him behind Soderling because Nadal's groundshots don't work that well on hard courts. Sure, he won the AO, one year ago, but that was mostly due to his astounding defending abilities, in both the semi and final.
5. Gulbis - what's there to say?...just look at his best performances and you'll understand. He hasn't quite had his breakthrough, but he'll get there if he puts a bit more dedication into it. Both sides are so powerful, there's plenty of variety, can hit pretty much everywhere on the court and as hard as Soderling even.
6. Del Potro: Sure, the CC forehand has caught everyone's attention and many will put him much higher in these standings, but I won't cave in. Del Potro won his USO, not only because of his groundstrokes, and anyone who has been watching his progress in the two years leading to his win at Flushing Meddow will understand where I'm hitting at. One thing he is impressing with is the versatility on his backhand side.
7. Berdych: Flatest shots you'll ever see when he goes for it. Lately he's been playing more controlled and has been way more patient which has led to some good results for him. He's still progressing and I don't think this Wimbledon final will be the last of him. Also should be noted that Berdych in his heyday (his choking days, as people refer to him) had the smallest net clearance level on average on the tour, and that showed in the number of UE's he made. Hits a very clean ball, backhand can improve a little IMO.
8. Nalbandian: Well, if you don't know the reasons why, just please escort yourself out of this forum.
9. Wawrinka: Best one hander on tour, and a very strong forehand, too bad he is mentally weaker than most players ranked near him, higher or lower.