This is based off of the current squads. If we sign Rooney I'd put us in front of City (marginally). I'd base the top few teams in 3 tiers. (Tittle challengers, Top 4 Contenders, and 'Best of the Rest' or least worst of the rest, whatever you like)
Tier One:
City - I think they have the best squad (in terms of quality and number of players in the prime) and have had a significant managerial upgrade as well as getting rid of trouble players (Balotelli and Tevez) and replacing them with good quality signings, though i'm not sure that they have replaced what Tevez offered them on the pitch.
Chelsea - Think our squad is still a little young and we don't quite have the squad that City do. If Toure and Fernandinho (who is a good player) perform well, with the addition of Navas and Jovetic, I think their squad might be too good for us over the course of the season. I still expect us to run them close. As I said before, signing Rooney would make us favourites IMO.
United - Lost arguably the best manager ever and replaced them with Moyes, who is not a bad replacement but is hardly in the same League as Sir Alex. SAF managed to get a rather average United squad to win the title last season (although City were sh*t and we had our November crash). They haven't signed anyone yet, their best or 2nd best player is massively unsettled and their pre-season has been absolute dog-sh*t (which I know isn't that important, but may be significant as it's Moye's first impression).
Tier 2:
Spurs - I have said this for the last 3 years and they have managed to bottle it but I expect them to finish ahead of Arsenal this season. Their midfield of Sandro, Dembele and Paulinho is very solid. They've finally brought in a reliable striker in Soldado and Lennon is pretty decent in the wide areas, whilst they also have Bale. If they don't keep Bale they will get a load of cash for him and, perhaps, their squad will be better for it. I also think AVB is a good manager despite his time here.
Arsenal - Still haven't signed anyone and I think their squad is worse than Tottenham's. If they get Suarez they will definitely challenge for top 4 again, but that's about it really. Their goalkeeper is not reliable and their midfield not as solid, and surely they will have their annual injury crisis.
Tier 3
Liverpool - Suarez wants out, seems like there is no way back for him now after his recent interview. They'll be able to get a few more players in with the cash they get but won't replace his quality. In Sturridge they have a good striker and Coutinho is a v. promising no. 10 but Gerard, as good as he is, is ageing and cannot/should not be able to play every game. Their defence is pretty sh*t despite what some Liverpool fans think and i'm not at all convinced by the 'Brendan Rodgers' doctrine of passing it around the back four until the opposition are comatose by their 'passing game'. This said, I still think they have enough to finish ahead of Swansea (who may beat Liverpool head v head, but not over a season) and Everton.
Swansea - I like Laudrup and think he has done a good job with Swansea and has made them more clinical. He has made some very good signings (notably, Bony) and maybe he has another 'Michu' up his sleeve. I'd honestly love it if they managed to finish ahead of the Scousers but I think over the course of the season they will struggle to get up to 6th place, especially whilst playing in the Europa league (which I hope they take seriously, but there is not much money in it). It would be hilarious if the club Rodgers left to join the 'Unique' Liverpool ended up finishing ahead of him, though.
Everton - No idea about them really, new manager could go one of two ways... Also the possibility of Moyes poaching his former players.
Rest...