Alexei Kovalev, formerly of the Habs, is the best remaining NHL free agent of the crop. Although it was widely reported on July 1 that he had agreed to a 2-year deal with Montreal with an annual salary of $4.4 or $4.5 million, this is clearly not the case. Monitreal has assembled their first line (Gomez/Gionta/Cammalleri) through free agency, and their is no room for Kovalev, despite fans' best efforts - several fans held a "rally" for management to re-sign this fan favourite.
So where will he end up? There's no doubting his talent. I watched Kovalev closely during his time with the Penguins, and he was a magician with the puck. Does he have a tendency to frustrate fans with his apparent lack of interest? Most definitely. However, for a team that believes it is a scoring threat away from sipping from Lord Stanley, despite his antics, he is a player I would sign to a 1 or 2-year deal without hesitation.
Looking at some rough salary cap numbers, about half the league can be ruled out of the running, along with the Montreal Canadiens. It is apparent that there are fans of some teams who desire Kovalev (see: Penguins) but it's just not economically feasible. The Penguins are after, first and foremost, a shutdown defenceman to help ease the loss of Rob Scuderi (and Hal Gill). After that, there's not enough cap space.
If I had to narrow it down to 3 teams who should be after Kovalev, they would be:
Atlanta Thrashers
Considering the Thrashers went after Nik Antropov and paid dearly for it (although I hear that Kovalchuk was the main driver behind this one), it would only make sense to add to the roster a forward who has much better skating skills and talent than Antropov...and for a price that barely beats what he is making. I am not sure what the relationship between Kovalchuk and Kovalev is, but on the surface it seems like a solid fit. Kovalev, for better or worse, has the pass first mentality, while it is no secret what Kovalchuk does best. This would work for a number of reasons, one being that this may be another piece to help keep Kovalchuk in Atlanta. I haven't heard this as a rumoured destination, but it makes the most sense to me.
Dallas Stars
This seems like the team that just won't go away. They seem to be able to bounce back from off years without any problem, and that's what they're going to be trying to do this season. It should be a better year with a healthy Brenden Morrow. The Stars' top right winger appears to be the recently re-signed Jere Lehtinen. Lehtinen's best years are behind him, and he's a defense first forward anyways. Kovalev would look nice on a line with Morrow & Richards.
Vancouver Canucks
They re-signed the twins, but it seems as though fans want more. And I don't mean Mikael Samuelsson more. The Canucks appear to want to fill the void that the departure of Mattias Ohlund left, so that might be their mission #1, but a skilled right winger would look good on this roster. Strictly going by the current depth chart, there seems to be a void on the first line, a right winger to play with the Sedins. I do understand that there may be some players who can play both wings, but I think a Demitra or Samuelsson won't do the trick.
There were some other teams that I left out. The Wild have cap room, and are now going to be playing under a new system with Lemaire et. al shown the door. They already have Havlat, and are rumoured to be going after Mikko Koivu's brother Saku. If Saku come in, I can't see Kovalev being brought in. There were rumours circulating that the Washington Capitals were interested, but I just don't see that they have the cap space, unless Kovalev takes less than the approximate $4.5 million he was offered in Montreal. Finally, the L.A. Kings, who were shut out of free agency in terms of star signings, are always the rumoured destination for players of this ilk. Hossa, Gaborik and Kovalev have all been rumoured to go to the west coast. I just don't see it happening. I think the main reason they're always mentioned as being in the mix is that they have over $10 million in cap space available to them.
I think the best fit would be in Atlanta, although I'm not sure how he would feel playing on a team with such a bleak immediate future, He'll prove me wrong, and sign in L.A.
Note: just as I publish this, I read that he has signed in Ottawa. That was my next guess