My priorities would be a GK, Right Back (if Sagna goes), back up CB (if TV leaves) a back up striker and a Holding/Box to box midfielder.
To be completely honest, I don't really think we need a first team striker as much as everyone says, I think Giroud will be a lot better next year, Podolski has been playing through an injury by all accounts, and we've just signed Sanogo. As a striker I'd love it if we signed Lukaku/Benteke, but what with Sanogo coming in I doubt it, and Jovetic hasn't really impressed me so much, again Benteke has better stats (although Jovetic has gone off the boil recently, maybe because of speculation?). Of all the strikers that we've been linked to the one that appeals the most is rooney, but that's not going to happen, wouldn't be too suprised if we bought Villa though, he's a short term measure who Sanogo could learn a lot from, will almost definitely give us a quality outlet, and would be a good alternative to Giroud if he doesn't work out next season. Still, my dream signing would be Tevez (attitude issues aside)
I think Cesar is a bit too flappy, hes always had concentration issues, even when he was the best in the world, think the reason he's looked so good for QPR is that he's always busy, put him at Arsenal where the shots aren't so common and I don't think he'll work out, but he would be a decent back up in any case. Mignolet/Adler would still be my preferred signings for that position though.
Would love it if we signed the polish RB (cbf looking up spelling) to replace Sagna (if he goes), but I doubt Dortmund would accept so many different changes, don't think Liechtensteiner is good enough defensively for us. Anyway, I love Jenko whenever he plays, and I'm sure we've got someone lined up if Sagna leaves.
Think we're covered at CB with Koscielny, Mertesacker, TV and Miquel (in that order), if Vermaelen goes he'd need to be replaced by another pacey cb (Miquel and Mertesacker are sloooow), the only one I know is Nkoulou (admittedly from FIFA)
From what I've heard, Fellaini wants to move down south, the North is a bit erm....grim for him, and I would take him in a heartbeat. Failing that, one of the Bender's would be good (probably would have a better chance of gettting Lars), or capoue/matuidi. Gonalons hasn't really impressed me when I've seen him, he seems like a younger arteta which isn't really what we need right now, I think Ramsey can take over that position in the future.
In terms of transfers out; Squillaci, Arshavin and Fabianski all have their contracts expiring at the end of this season, which frees up around 180k a week from what I've seen. Sagna and Denilson will be sold to PSG and Sao Paolo respectively I think, with Chamakh probably going to Bordeaux for a tiny transfer fee, Coquelin appears to be gone, and we might see the back of Park and Gervinho too. I think we'll be stuck with Bendtner for another year, who could be a decent back up if he gets his head sorted out (we can only hope). If we do sell Gervinho, I imagine we'll buy a winger on the cheap as well.